Check Engine Light Codes

Intermittent NO SPARK on 1994 Ford Taurus with 3.0L engine: NO CODES

2007-03-24T18:33:00.000-07:00

Question:

What could cause my 94 Ford Taurus to quit intermittently? When I scanned it, there is no code and even after I replaced the ignition module, same thing happens. This symptom can happened anytime, anywhere which makes this car unsafe to drive!

ATS Adviser:
If you have already replaced the ignition module, most likely the pickup coil inside your distributor is the culprit. To check, take the distributor out (make sure you mark the distributor housing and point the rotor to #1 position) and measure the coli resistance in ohms. Sometimes, you need to apply a heated air to the coil like a hair dryer. To get the right specs in ohms, contact ATS.

No spark and no fuel on 1991 Mitsubishi with 4 cylinder engine: NO CODES

2007-03-22T11:07:00.000-07:00

Question:

My sister's car quit yesterday and when I checked it, there was no spark on the plug wires and no fuel going to the throttle body. There was no code when I scanned it but the distributor has the power going to it. I replaced the distributor with a rebuilt one but the same thing happened: no start!!! This is getting very frustrating and I need your help. Thanks.

ATS Adviser:

Based on your symptons, I would check the power and ground supplies going to the ecm (computer). First of all the ecm grounds your distributor in order to work and most likely, that is the culprit however, check your ground and power supplies first as laid out in ATS courseware. If you need the ecm diagram, just let me know.

P0420 code on 1998 Honda Civic with 1.6L engine

2007-03-21T08:43:00.000-07:00

Question:

This car has an intermittent code P0420- catalyst efficiency low coming on and when I checked the downstream oxygen sensor, it was responding properly. I decided to replace the CAT (catalytic converter) buying an aftermarket one from a local muffler shop so I can save money (the CAT from the dealership is very expensive). After road testing, the light came back. The muffler then advised me to replace the downstream oxygen sensor but it did not fix the problem. What should I do?

ATS Adviser:

There is high rate of failure when using aftermarket CAT and most garages recommend using only OEM CAT from Honda especially on 1996 models and up. If you put an oem CAT on this, the code will stop coming back provided the oxygen sensor wires are not shorting out. Also, when testing the oxygen sensors for this engine, the upstream sensor is used for engine fuel management whereas the downstream sensor is used to monitor CAT efficiency.

Cruise control won't work on 1998 Chevy Cavalier: No codes

2007-03-19T20:12:00.000-07:00

Question:

This is my grandma's car and she complained to me that the cc (cruise control) suddenly won't work after making a long highway trip. I checked for codes but could not get one. A friend mechanic advised me to replace the CC module or control unit but my sister has a similar car and I substituted her part to this car. This did not work either and I am running out of hair trying to figure this out. Suggestion?

ATS Adviser:

Before you get deeper on this problem, try checking the 2 rear brake lights for proper operation. A lot of times, a broken brake bulb can kill your cc and all you do is to check the bulb socket or the bulb itself. If they are OK, check the 3rd brake light too in your rear windshield. If these don't fix this, let me know so I can send you the complete wiring diagram of the cc circuit so you can check the ground and power supplies.

Battery goes dead if left after 5 days on 2001 Nissan Pathfinder: No codes

2007-03-18T11:06:00.000-07:00

Question:

Why would my battery goes dead if I leave it parked for 4-5 days? There is no code when I had it scanned at a local parts store and I also replaced the battery. Also, on the 3rd day, I can hear the starter laboring before the engine starts. This only started happening after my son installed an aftermarket remote starter 1 month ago. Please help.

ATS Adviser:

It's good you mentioned the aftermarket remote starter because there are lots of problem going on with them these days. It is recommended that when installing a remote starter that you get it from the dealer and they can even hook it up correctly. If the wiring connections are not right, it can create a battery drain causing your symptoms. To check, disconnect this aftermarket remote starter wiring connection and monitor your starting system again. If this problem stops, then that is the culprit.

P0133 Code for 98 Saturn with 1.9L engine.

2007-03-17T20:02:00.000-07:00

Question:

This car has a code P0133- 0xygen sensor signal slow and when I tested it using a voltmeter, I got 0.4 volt with key on engine off. When started and warmed up, the reading was fluctuating between 0.1 volt to 0.9volt as it should be. However, even after I changed the sensor, the code returns and got the SAME reading. Is this a computer problem?

ATS Adviser:

Before you condemn the computer, check the ground wire for the oxygen sensor located on the transmission mounting stud. If OK, I would check the oxygen sensor wirings at the ecm itself. There is a chance the wires could be open or shorted thereby givig you the code. If you still get the same readings, then you can also check the ground readings of the ecm and bring the same to the dealer for replacement or re-programming. ATS can provide you with the ecm wiring diagram so you can check all the pin voltage readings.

Battery light is on and alternator not working on 1997 Odyssey Honda with 2.2L engine: No codes

2007-01-23T15:33:00.000-08:00

Question:

My wife's 1997 Honda Odyssey battery light is on all the time and the alternator won't charge. I replaced the alternator with a rebuilt one from our local parts store but the problem is still there. A friend mechanic told me to replace the ecm (computer) but I am not sure if this will fix the problem. Can you help?

ATS adviser:

There is an electrical load detection (ELD) unit located at the fuse box under the hood. Check the pin wire #2 with grn/red color and see if it is connected to the pin#16 in your ecm. This is a control wire from the ecm to your alternator. To check, run a jumper wire between those pins and if the alternator starts to charge, replace the alternator. Finally, if you bought the alternator locally and not from Honda, I guarantee your alternator will not work.

ATS tip:

When testing the LED unit, make sure the ground wire at pin#1 is clean and secure. To get the wiring diagram for the charging system, contact ATS.

P0303 misfire code for 1997 Ford Wind Star with 3.8L engine

2007-01-22T13:26:00.000-08:00

Question:

This 1997 Wind Star is having a misfire code after the engine is warmed up. When scanned there is no coolant sensor code except this misfiring code. The engine has a lot of mileage but when we checked the compression, readings are all above 140 psi. No engine coolant was found in the oil and I think the engine is fine. testing the vacuum confirms that the reading is well above normal.

Testing the injectors shows the same reading and when I checked the spark quality while idling, I have a steady blue strong spark. I am now inclined to suspect that we might have a computer problem. Do you agree?

ATS Advisor:

There are a few tests you can do on this code: 1.) try switching the plug wires and see if the misfire code will change to another cylinder. 2.) did you clean the mass sensor? usually this will not cause a misfire code. 3.) tried disconnecting the egr valve? if misfire stops, then egr system is faulty. 4.) if all of the above fails, remove the intake plenum at the intake manifold and most of the time, the seals and O rings for this plenum leaks causing a misfire code when hot.

Car hesitates on 1999 Cavalier with 2.2L engine: No codes

2007-01-21T09:58:00.000-08:00

Question:

I have a 1999 Cavalier and lately, I have an intermittent hesitation and misfiring and the check engine light will come on in the dash. However, if I scanned it, my scanner will not communicate with the engine computer (ecm).
What do I do?

ATS Advisor:

There is common cause for this problem and it is attributed to the poor location of the ecm. If you look under the front fender of the car and remove the cover, you will see the ecm. A lot of times, because it is too close to the ground and rain water when you are driving, the wire terminals to the ecm will be corroded. When that happens, the wires will be covered with "green stuff" and later the wire can have a poor contact or even break. Try wiggling the wires to the ecm and find which wire is broken. Repair if necessary.

If the ecm will still have no communication with your scanner, remove the ecm and test all the ground and power supply wires as per ATS past newsletters (testing ecm). If the readings are normal and reference voltage is erratic, replace the ecm.

ATS Tip:

To get a detailed wiring diagram of your ecm, please contact ATS.

P0402 code for 1999 Nissan Altima with 2.4L engine

2007-01-20T22:19:00.000-08:00

Question:

Have this code P0402-egr control back pressure transducer valve on my Altima and when I tested it, found the egr valve sticking. Replaced the valve and also cleaned the passage tubing going to it. After resetting the code and road testing it, the code light went out. however, after a week of using, the same code came back. I re-check the egr valve and I cannot find anything wrong. Please help.

ATS Advisor:

When testing your egr system, try these:

Check all your egr vacuum hoses for cracks and connection

There is a restrictor inside the vacuum hose for the EGRC-BPT valve, that cam be tested for dirt restrictions due to carbon

The egr valve flow can be tested by lifting the spindle with your finger during idle and the rpm should go lower.

If the above code persists, replace the egrc-bpt valve next to the egr valve.

Code P0301 on 2001 Pontiac Grand Am with 2.4L engine

2007-01-19T17:15:00.000-08:00

Question:

My 2001 Grand Am has a misfire code P0301 when scanned. The engine was also quitting at stop lights. Initial repairs included replacing the spark plugs that included the ignition coil. After doing all of these, misfiring is still present and I am now thinking of replacing either the ignition module or the engine computer. Any suggestion?

ATS Advisor:

The most common cause of this misfiring is a shorted ignition coil housing. When you replaced the spark plugs, the housing should been checked for heat burns on the housing which will verify such condition. shown on top is a picture of the housing. If you invert it, most heat burns will occur between the spark plug mounting holes.

Code 32 on 1990 Corsica with 3.1L engine

2007-01-18T19:14:00.000-08:00

Question:

This 1990 Chevy Corsica has a code 32-egr system fault after I scanned it with OBD1 scanner. When I checked the egr system, I found that I have an egr electric solenoid instead of an egr valve. How do I proceed to test it?

ATS Advisor:

To check the egr solenoid is quite simple. start and run your engine at idle and put a jumper wire on each of solenoid 3 wires. When you do this, each solenoid will be activated causing it to open up and should cause your idle rpm to change. If all 3 solenoids do not make any changes, stop the engine and remove the egr solenoid. When removed, check first for the opening where the solenoid was mounted. If the hole is clear of carbon, replaced the solenoid, otherwise clean the egr passage hole.

ATS can supply you the wiring colors of each egr solenoid wire.

Serpentine belt installation for 2003 GM p/up truck: No codes

2007-01-12T11:11:00.000-08:00

Question:

This truck's engine serpentine belt was sqealling and before I could replace it, it broke on me, how do you replace it?

ATS Advisor:

If you open your hood compartment of your truck (see picture) you will see the diagram of the serpentine belt routing. You can follow that and when you buy a new one, the package of the belt will also show a diagram for it. Make sure you give the parts store the accessories that you have like AC so they can give you the right lenght of belt.

After market water pump for 2003 Honda Civic has to be changed twice in the last 3 months: No codes

2007-01-07T21:17:00.000-08:00

Question:

Why would my water pump started to leak 2 weeks after I replaced it and AGAIN after almost 3 months? I bought this water pump from a local parts store and I also flushed the cooling system to make sure the coolant circulating is clean (engine has over 100k miles). Do I need to use a special coolant for this vehicle? Your insights would be highly appreciated.

ATS Advisor,

First of all, stay away from after market parts when dealing with imported vehicle like Honda. You can buy an OEM (original) part from the dealer and you can avoid all this head aches. when replacing the coolant, use the one recommended by the dealer and mix it 50-50 with water. If you need more assistance, just contact ATS.

P0123 TPS Code for 2000 Jeep Sport Cherokee with 4.0L engine

2007-01-05T20:15:00.000-08:00

Question:

This 2000 Jeep Sport Cherokee has this check engine light coming on and when scanned, a code P0123-tps voltage abnormally high showed up. Ever since this happened, my cruise control quit working and the engine keeps stalling making it difficult to drive in heavy traffic. Measuring the tps voltage using ATS wiring diagram showed the tps is defective. We replaced the tps sensor but it did not fix anything. Thinking it might be the computer, we replaced that too and STILL the same code! Please help!

ATS Advisor:

This is a common problem and you should have contacted ATS before you replace those parts. The problem here is a faulty clock spring hooked up to your steering column. What is happening is the clock spring circuit is shorted and it is also connected to your tps circuit. To test, unplug the connection to the clockspring and your tps should work. Most of this problem is usually solved by replacing the clock spring. If the clock spring is fixed, it will fix the cruise control also.

ATS Tip:

A step by step procedure in replacing the clock spring is available from ATS if you are a member.

P0171 and P0174 codes for 2000 Hyundai XG300 with 3.0L engine

2007-01-02T16:22:00.000-08:00

Question:

This 2000 Hyundai XG300 runs pretty good but 3 days ago, the check engine light showed up accompanied by codes P0171-Bank 1 system too lean and P0174-Bank2 system too lean. My vacuum reading looked normal and I did a quick tune up like replacing all filters and spark plugs. Since the oxygen sensors have not been replaced since the car was new, I replaced both the upstream sensors. The downstream sensors (after the CAT) are not used to monitor engine fuel mixture so I left them alone. However, after doing all of these, the light came back with the same code. Suggestions?

ATS Advisor:

The most common cause of this problem is a dirty or faulty mass sensor. You can service that by cleaning the sensor wire elements as per ATS course. If you see any improvement after servicing but the code returns after a few days. Replace that sensor too. In case this fix will not work, here are other areas to explore:

Are you using premium gasoline? It would help if you it and may also improve performance.
Have you done fuel chemical tune up? If the engine has too many miles, the injectors could build up varnish and ultimately carbon in the combustion chamber causing this lean condition.
Adding chemical additive to your fuel tank can help remedy this. however, if the code persists, have the injector serviced by a garage.

Code 41 with severe stalling on 1993 Dodge Caravan with 3.3L engine

2007-01-01T09:45:00.000-08:00

Question:

My minivan has poor power accompanied by hesitation on acceleration and stalling on stop signs. When scanned, I have code 41. I have checked the engine for mechanical condition and seem OK. Using your ecm test, I found the engine acting up when the ecm is tapped with a rubber mallet. I decided to replace the ecm and it worked good for a couple of days. After that, the problem returned with the code 41. Please help.

ATS Advisor:

The first thing I would check here is your alternator. There are a lot of reports indicating this is a common problem especially on high mileage minivan with this model. Check the alternator for proper ground or have it tested for proper output. If this won't fix it, have the bcm tested also for ground connections. If you read my earlier blog, bcm testing is discussed extensively. Always reset the ecm every time you perform any repair.

No HEAT in truck cab for 2000 Durango: No Codes

2006-12-31T13:21:00.000-08:00

Question:

I have driven this 2000 Dodge Durango truck since new and starting last week, my passenger side carpet under the dash is wet with coolant fluid. When I drove the truck, a foggy smoke came out of the dash vents. Reading your ATS course, I suspect my heater core is toast and needs replacement. Is this a job I can do?

ATS Advisor:

I believe this truck has an AC and if you do, the heater core is embeded inside the evaporator housing which is located in the front passenger side under the dash. To remove, the evaporator housing must be drained first of freon and then you can remove the housing. Attached is an example of the truck cab showing the passenger side. Make sure to mark and label all the parts that you remove and always compare the heater core housing that you will buy.

Once installed, you can put back the freon that you remove or have a garage evacuate the AC systen for you to prevent introduction of moisture to your AC. If you ca do this, you should be able to save money in the replacement of your heater.

No Start on 2000 Dodge Intrepid with 2.7L engine: No codes

2006-12-30T10:37:00.000-08:00

ATS Question:

My wife's car suddenly quit on her while she stopped for groceries. She had it towed to our garage so I can check it. I found the engine with no spark but I could not test the injectors because there is no room for it. Electronically, I tested the asd relay and the ignition coil and both seemed to have good power and ground. I am now at a loss on how to proceed to check the problem. Do you have any suggestion?

ATS Advisor:

You are very lucky because this problem is very common on 1999-2000 models. All you do is unplug the camshaft sensor and try starting again. You might have to be patient because it requires long cranking but it should start. When it does, observe these: if it starts without making a noise in the engine, the culprit is usually the camshaft sensor. If it starts but making a lot of engine noise, the timing chain is usually the problem which requires the opening of the front timing cover.

Tip:

To get the exact location of all the above components, contact ATS if you are a member.

No spark for 1992 Olds ninety Eight with 3.8L engine: No Codes

2006-12-11T12:01:00.000-08:00

Question:

My car quit on me yesterday and following ATS course, I found it has no spark. As per your lesson, this problem is caused by crank sensor and ignition module. I first replaced the crank sensor and found still no spark. Went and got a new ignition module and same thing happened. But after spending all these money for parts, I still have no spark? What am I doing wrong? Is my engine computer buggered up too?

ATS Adviser:

First of all, although ATS fixes tells you to suspect both crank sensor and ignition module, there are a few tests involved before replacing those parts. Examples:

Did you check if the crank sensor has proper ground and power supplies? If you requested the ignition wiring diagram, you can see the ground and power supply wires. Always go to the basic: Ground wires should read 0.250 volt or less with key on engine off. Power wires always give you around 12 volts with key on engine off.

These simple tests will tell you if there is a problem with the sensor or ignition coil. The same is true if the wirings connected to them. Those parts might be OK but if the wires are shorted because the insulation is bare, your new parts will not work still.

Finally, a lot of local parts stores can test those parts for you and they can tell if the parts are OK or not. If they say the parts are tested OK, then it gives you a red flag to test the wires or the ecm (engine computer). Again to test the ecm, all you do is test what? The ground and power supply readings at the terminal of the ecm with key on engine off PLUS, the reference voltages. This is the most basic tests of ATS troubleshooting and if you use this method, you will solve about 90% to 95% of engine electronics problem.

ATS Tip:

When testing your wires, use wiggle tests and wiring diagram to trace the shorted wire.

Boosting your battery cables can be deadly...shuts down whole systems: No Codes

2006-12-01T11:59:00.000-08:00

This is just a reminder for everybody during this cold weather

When boosting your vehicle battery, remember these:

Connect cables colored RED to RED or red cable to red post at battery (positive)
Connect cables colored black to black or black cable to black post at battery (negative)

Always connect the positive cable first and negative cable last

Always disconnect the black cable first and red cable last.

Shown in the picture is a 2005 Altima with a blown cable terminal fuse after the cables were connected wrong. Problem? Fuse comes integral with the positive cable. now you have to buy the positive cable assembly. What a waste of time and money! Finally, here is another drawback in this Altima...the whole engine shuts down and cannot be re-started until you changed the fuse/positive battery cable (available ONLY from the dealer of course).

Code P0302 causing misfire for 1996 Pontiac Grand Am with 2.4L engine

2006-11-29T09:06:00.000-08:00

Question:

Four days ago, my Grand Am started misfiring and when I scanned it, I got code P0302 cylinder #2 misfire. Using your earlier advice, I removed the top valve cover and run my own plug wires and switched #2 cylinder with #3 cylinder but the misfire stayed at #2. Switching the ignition coils also made no difference. Because the vacuum hose going to the fuel regulator was wet, I changed the fuel regulator and again made no difference. All the compression readings were over 200 psi and I am losing my wits on what to do next. Your help will be much appreciated.

ATS Adviser:

Since you got the valve top cover out, you might as well do a balance injector test as described in ATS Course. Another quick way to do this is to switch injector #2 to another injector like #4. Then make sure the engine is warmed enough and see if the misfiring will remain in #2 cylinder. If it moves to cylinder #4, you know pretty well that the problem is the injector.

ATS tip:

The fuel regulator although defective in your case, will not cause misfiring. It will make your engine fuel mixture to flood or rich though and cause hard long starts.

Code 181 for 1994 Ford Escort 1.9L accompanied by hesitation and cutting out.

2006-11-27T07:38:00.000-08:00

Question:

My mother's Ford Escort would hesitate only when running at highway speeds as if the engine is running out of gas. When this happens, the engine would also stall and finally quit. It will re-start but it has no power. She had the IAC (Idle Control) valve replaced but the problem remains and she asked for my help. I plan to do a major tune up like spark plugs, wires and fuel filter. What bothers me though is when I scanned it, it has code 181 which showed cruising rich and bank 1 lean. Is this problem serious? Can I fix this myself?

ATS Adviser:

First and foremost, check first if you have a vacuum leak which can cause your engine to run lean. Next is to check the voltage readings of your oxygen sensor and see if it fluctuates (see ATS courseware). This sensor seems to be a common problem on this model especially with this code and symptom of hesitation. You can also check these:

1.) Service the mass sensor for dirty wire elements
2.) Check the fuel regulator for diaphragm fuel leakage
3.) Check pcv valve for crack that would cause vacuum leak

You should be able to do these checks by yourself if you read the ATS lessons given to you but I would concentrate your effort to check if the voltage reading of the oxygen sensor is not stuck (this will show that the sensor is defective).

ATS Tip:

A bad running oxygen sensor can disrupt your fuel mixture and would cause hesitation and loss of power.

P0340 code for 1997 Toyota Camry with 2.2 L engine

2006-11-23T09:28:00.000-08:00

Question:

My uncle's 97 Camry has the dash check engine light coming on all the time. Found code P0340 which stands for camshaft position sensor fault. He changed the camshaft sensor and the engine ecm (computer) but the light would come up after driving it for a few miles. He asked me to help him and I just want your assistance before I see him. Note: This vehicle has a lot of mileage on it.

ATS Advisor:

If the vehicle has too many miles and the timing belt has not been replaced, most likely the belt is either loose or has skipped a tooth. When this belt is loose or out of timing, the ecm will get an erratic signal from the camshaft sensor and will trigger this code. This is usually occur with rough idle and lost of power. Try this first and if this won't work, pull out the distributor and check for worn drive gears.

ATS tips:

If timing belt is out of timing, the vacuum reading is usually low (15 inch or lower) accompanied by low compression reading.

Instructions for changing the timing belt are available from ATS if you are a member.

BCM (body control module) Testing Summary

2006-11-22T05:32:00.000-08:00

When performing test for your body control module (bcm), here are some quick tips in testing this module:

Get hold of the bcm wiring diagram from ATS. Using the bcm diagram, you can identify all the components that being controlled by the bcm by using the wiring colors associated with the part or component. A lot of times, the location of the component is described in the wiring diagram. BCM components usually include lights, power mirror, window and door locks, anti-theft, windshield wiper system, radio, instrument cluster, horn, all vehicle openings like trunks, defogger, power steering, AC, cruise control and other accessories.

The first test of the bcm is using a scanner. It will tell you right away which part of the bcm system is malfunction. It can also isolate the particular circuit in the bcm to narrow down your test. Remember: bcm code is not the same as the engine code.

To test the bcm, start by checking the ground pins for voltage which must not be higher than 0.250 volts. If it does, it means there is a short in the wires or one of the components. To verify, unplug the components one of the time until the voltage reading returns to normal.

Make sure all connections to the bcm and components are tight and not corroded.

The BUS plus and minus communication pins at the bcm can be checked and it should measure about 2.5 volts (ask ATS for the exact voltage for your vehicle) with key on. If none or higher voltage reading, it indicates an open wire or defective bcm or component. Again try to unplug the component one at a time to test.

ATS tips:

When working with bcm, always read all the blog posts by searching the word "bcm" on the top left corner bar of this blog and click "search this blog" beside it.

BCM when replaced needs to be reprogrammed by the dealer when bought new. When buying one from the salvage yard, make sure it is the same match for your vehicle. Sometimes, the bcm does not include the alarm system and can cause future problems.

P0303 code for 1998 Ford Taurus with 3.0L engine.

2006-11-20T07:24:00.000-08:00

Question:

My check engine light keeps coming on and got a code P0303 misfiring code on cylinder #3. I checked the compression on this cylinder and it is comparable with the rest. I have no vacuum leak and got 18 inch when I measured it. I swapped the injectors from #3 to #1 cylinder and after a week, the code still returned for #3. Finally, this code is also intermittent and I am about to bring it to the dealer if you have any suggestion.

ATS Adviser:

Going by ATS database, one fix that you might have missed is the ignition coil pack. Have you tried switching the plug wires too? If the coil pack is borderline defective, it will run OK and might test well if you measure it with a voltmeter. However, if it is used for a few days especially under load, it might start to falter and show you the code. That would be the test I would do if I were you before going to the dealer.

ATS Tip:

You can also use an electric air heater and apply it to the coil and see if the part will fail.

1997 FORD F150 P0401 EGR Flow code with 5.9L engine

2006-11-18T11:20:00.000-08:00

Question:

As per your ATS instruction manual, I changed the egr valve, dpfe sensor, egr solenoid including the blowing of air passages of the egr system of this engine yet this same code keeps coming back. Am I missing something? I also reset the code but the check engine light with the same code is on all the time.

ATS Adviser:

Although you replaced all those parts, you did not indicate if those parts are from Ford which makes a lot of difference. Sometimes when you use 'aftermarket" parts, the quality might not be comparable. Also, when you said you blew the passages of the egr system with air, did you remove the throttle body? The carbon build up inside the intake manifold ports is very difficult to remove unless you take out the throttle body.

ATS Tip:

When the same code appears, it shows the problem is not solved like restricted flow.

1997 Intrepid wiper motor won't stop even with key off: No codes

2006-11-16T11:30:00.000-08:00

Question:

The windshield wiper motor will not stop until the fuse is taken off. I am scratching my head here because I thought replacing the wiper motor would fix it but to my surprise, it did not change anything. Suggestions?

ATS Adviser:

Symptom such as yours could be fixed by replacing the wiper motor because of a bad park switch located inside the wiper motor. However, a lot of this problem is also caused by a bad ground at the wiper motor housing and you can correct that by running a ground wire direct from the battery negative to the wiper motor housing. Assuming that won't fix it, replace the multi-function switch at your steering wheel.

ATS tips:

To verify the integrity of the wiper components, ATS can supply you the complete wiper motor wiring diagram so you can test the circuit.

2000 Grand Prix with 3.8L engine intermittently quits after driving for 5 miles: No codes

2006-11-15T11:21:00.000-08:00

Question:

This car quits after being driven for 5 miles. It starts right away when re-started but I am puzzled because there is no code when scanned. I cannot check the spark or fuel signal because this happens quickly and there is no changed even after I changed the ignition module. Please help.

ATS Adviser:

Most of the symptoms you gave points to a defective crank sensor. It is located behind the front crank pulley which must be removed to access the crank sensor. Before doing it, make sure all the wiring connections to the sensor is not shorted. After replacement, reset the code and take it for a road test to confirm the fix.

ATS tip:

If after the sensor is replaced and problem re-occur, you need to check the ecm (computer) wiring terminal integrity of the ground and reference voltage signals so we can check that too.

2000 Grand Prix with 3.8L engine intermittently quits after driving for 5 miles: No codes

2006-11-15T10:06:00.000-08:00

1996 Ford Taurus ps pump shooting oil as soon as the car is started: No codes

2006-11-14T10:00:00.000-08:00

Question:

My sister's 1996 Ford Taurus has a weird problem: the power steering pump shoots oil as soon as the engine is started. We installed a new power steering pump and the same thing happened. How do you fix this?

ATS Adviser:

This car's steering system uses a rack and pinion and most likely, it is shot and not allowing the oil to pass through. When that happens, oil pressure builds up in the ps pump and is forced to release it on the pump itself. This is what you are seeing during the release. To fix, replace your rack and pinion.

ATS Tip:

Make sure to flush the entire steering system after the rack and pinion is replaced.

Code 44 on 94 GM Safari with 4.3L VORTEC engine

2006-11-13T06:43:00.000-08:00

Question:

The last few days, I am getting poor acceleration on this engine. When I scanned the codes, I got code 44 -lean exhaust. I have done a quick tune up consisting of spark plugs and wires including the fuel filter. I also changed the oxygen sensor and all of these did not seem to help. It used to bog down once a week and now it is doing it every other day. What do I do? (Note: I also tested the fuel pressure and it was 56 psi at idle).

ATS Adviser:

The give away for the fix of this problem is the fuel pressure. Any vortex engine, the fuel pressure reading is critical. It should not go down below 60 psi or you will have this symptom. Your reading is low and you need to replace the spider injector located under your engine plenum. About 90% of the time, replacing the injector (see picture) will fix this problem. If not, check the magnet of your distributor shaft.

ATS Tip:

ATS can supply you the step by step procedure in replacing the centralized spider injector if you are a member.

1994 Ford Ranger Engine surges when AC defogger is tuned on: No Codes

2006-11-09T17:47:00.000-08:00

Question:

My engine runs OK as long as I don't use the front dash defogger. If I set the AC button to floor setting, again engine runs fine. I scanned for codes and there is none. Can you give your insights on this problem?

ATS Advisor:

When you set your AC button to the defogger mode (see picture), the AC is actually activated and is controlled by Freon pressure which is monitored by your AC computer. When this happens, the AC computer signals the engine computer to raise the rpm to prevent the engine from stalling. However, if Freon pressure is low, the AC clutch is de-activated which cause the AC system to stop and rpm goes down. With these two modes, it will create a high or low rpm or surging condition. Try testing your Freon level and top it up with freon if possible.

ATS Tip:

Putting your AC setting to the floor mode de-activates the AC system causing your engine to run normal because the AC computer is not controlling the engine rpm anymore. ATS can supply you the Freon pressure specs for this vehicle.

Code 35 erratic engine idle for 1993 Pontiac Grand Am with 2.3L engine

2006-11-06T04:04:00.000-08:00

Question:

My wife's Grand Am has a rough idle and it has code 35 when scanned. As per ATS info, most of this problem is solved by fixing a vacuum leaks.Is there a quick way to do this?

ATS Adviser:

Most vacuum leak can be found by runnning the engine at idle and using a propane bottle (use for soldering cooper tubings), by feeding raw propane gas on all vacuum lines and intake manifold gaskets. If you hit the vacuum leak, the engine rpm will usually change indicating a vacuum leak. Some mechanics use carburator cleaner spray can in place of the propane but can pose a fire hazard when sprayed on exhaust. To be safe, you can also spray mist of water from a spray bottle for the same effect. On most 1994 Grand Am 4 cylinder engines, the engine leak can be found on the corner of the intake manifold.

ATS Tip:

After finding and repairing the vacuum leak, reset the code to confirm the fix.

1993 Cavalier 2.2L stalls at stop lights but will re-start in 15 minutes: No codes

2006-11-05T13:14:00.000-08:00

Question:

My daughters car is stalling at stop lights and if she waited for 15 minutes, it
would start again. I changed the spark plugs and fuel filter and the stalling
still happens. I scanned for codes and there is none. How do I fix this?

ATS Adviser:

If you have to wait for 15 minutes before it starts, always check for spark at your plugs. If none, the problem is usually your ignition parts. Crank sensor would be the first choice even if it tested OK. You can check that by hooking a test light from your battery positive and tap the purple white wire at your ignition module connection (do this with key off). If the injectors start clicking when you touch the injectors, the crank sensor is defective and the module is OK. Otherwise, replace both module and the ignition coil.

ATS Tips:

If no starts occurs after warmed up but re-starts right away and dies again after you put it in gear, the tcc sensor is defective. you can unplug it from the side of your trany and road test again. If symptoms stop, then it is definitely a tcc sensor problem.You can leave it unplugged but you might loose some fuel mileage.

ATS can supply you the ignition wiring diagram so you can trace all the wires and location of the ignition parts.

P0506 IAC code on Ford F150 with 4.6L engine.

2006-11-01T21:59:00.000-08:00

Question:

My F150 pick up truck has a bad rough idle and would surge/stall at times. After scanning, I got a code P0506- Idle air control system rpm fault problem. Does this mean I have to change the IAC motor?

ATS Advisor:

As per wiring diagram, there is no IAC motor for this engine and I suspect you have an error code. You can try resetting the computer by disconnecting the battery negative terminal or using your scanner. For your rough idle, I would try testing for vacuum leak by using a smoke machine recommended by ATS. The rpm on this is controlled by the electronic throttle control motor located in the throttle body with the help of the electronic throttle control module located in the accelerator pedal bracket. However, since there is no code on these TP sensor and module, I would try cleaning first the TB plates with intake spray and then blow it dry with air. The throttle plates are known to build up carbon deposits and causing rpm problem.

ATS Tip:

There is an extended warranty for emission on this engine and you should contact Ford to verify it.

Intermittent NO start and no scanner communication for 2002 Chevy Blazer 4.3L with no engine codes

2006-10-31T17:42:00.000-08:00

Question:

What can cause my scanner not to communicate with my engine computer during no start. When this intermittent no start happens, the shift PRNDL indicator will also quit together with the dash lights. As per your blog, we changed the bcm module but the problem remains.

ATS Adviser:

That bcm will not apply here because the symptoms are entirely different,your symptoms: no start + no scanner communication + no PRNDL signal means a defective ignition switch. During no start, go to your steering column and check the yellow wire at the ignition switch below the steering wheel. If there is no power (12 volts) at the wire, the ignition switch is defective.

ATS Tips:

The ignition switch can be replaced without removing the steering wheel. Use ATS wiring diagram as a guide when locating components.

Windshield washer keeps freezing on 2002 Ford WindStar: No engine codes

2006-10-30T04:58:00.000-08:00

Question:

How do you keep the windshield washer fluid from not freezing in the windshield? I have to stop my minivan every 20 minutes to clear the blades of ice and it is very frustrating. Help!

ATS Advisor:

Here in Canada, we use a winter anti-freeze windshield washer fluid which does not freeze in your blades. This fluid should be available in most local automotive parts store. Also, replace your windshield washer blades with winter type blades which are coated with rubber and helps prevent the blades in forming ice between the blades and the windshield. Finally, make sure your windshield defroster is turn on to heat up your windshield while your engine is running.

ATS Tip:

The air vents to your windshield defroster must a good flow. Any restriction will prevent heated air from going to the windshield. For proper servicing of the windshield washer system, contact ATS.

P1695 no communication code for 1997 Dodge Caravan with 3.3L engine.

2006-10-29T17:39:00.000-08:00

Question:

My check engine light is on and my dash gages are not working. The ABS light is also on and when I scanned the codes, this is what I got: P1695 no communication for CCD bus lines. How do I check this?

ATS Adviser:

If you read my previous posts about BCM, you can measure the bus line voltages of your BCM terminal pins. With key on, you should get 2.5 volts. Higher voltage could mean a short somewhere in the BCM or in other modules connected to it. You can test it by watching the voltage of the ccd bus lines and disconnecting the other module one at a time. Example: let's say you have a reading of 5 volts which is higher than our requirement. Assuming you have a few modules like AC heater control, instrument cluster, radio, ABS, Air bag, trany control and pcm. If you disconnect this one at the time and the ccd bus voltage returns to 2.5 volts, the last module that you touched is the culprit.

ATS Tip:

The most common module to go on this case is the instrument panel attributed to poor solder connections at the terminal. Take a closer look and inspect the solder and repair if necessary.

ATS will provide a wiring diagram for the above modules upon request.

P1695 no communication for 1997 Dodge Caravan with 3.3L engine.

2006-10-29T08:34:00.002-08:00

P1695 no communication for 1997 Dodge Caravan with 3.3L engine.

2006-10-29T08:34:00.001-08:00

P1695 no communication code for 1997 Dodge Caravan with 3.3L engine.

2006-10-29T08:34:00.000-08:00

P1695 no communication code for 1997 Dodge Caravan with 3.3L engine.

2006-10-29T06:20:00.001-08:00

P1695 no communication code for 1997 Dodge Caravan with 3.3L engine.

2006-10-29T06:20:00.000-08:00

P0121 tps sensor code for 2001 Ford Focus with 2.0L engine.

2006-10-25T07:37:00.000-07:00

Question:

My sister's 2001 Ford Focus check engine light is on and it is hesitating. After scanning for codes, I got P0121 which is a faulty tps sensor. I am new to this ATS but I have a digital voltmeter, can you send me the procedure in testing this code?

ATS Advisor:

On this tps sensor, you have 3 wires. On one end is the ground wire and the other end is the reference voltage wire. The middle wire is your tps signal voltage. Check out the ground wire and reference voltage wire at the sensor itself. The ground voltage should give you 0.250 volt or less with key on. If reading is higher, you have a shorted wire in your ground wires or the tps sensor. The reference voltage is almost always fixed at 5 volts. Finally, the signal wire is best checked at ecm (computer) terminal pin. With engine at idle, expect to get 0.5 to 1.2 volts. At high idle, the reading goes up to roughly 4.5 to 5.0 volts.
If you are not getting these readings, repair the wires or replace the tps sensor.

ATS Tip:

When you get the ATS wiring diagram, the ecm pin wire color and designation will be shown to you.

P0340 camshaft sensor code for 1996 Ford Taurus with 3.8L engine

2006-10-24T06:22:00.000-07:00

Question:

My car is hesitating and came with this code P0340 which is a camshaft sensor fault and my mechanic replaced it including the synchronizer that goes with the camshaft sensor. However, the check engine light stayed with the same code and the hesitation is still there. I am not sure if we did this job properly or we bought a defective sensor. Please advice.

ATS Advisor:

First of all, this code is not caused by defective camshaft sensor alone. It can be triggered by a fault in the egr system especially the DPFE sensor which emits electrical interference and interfere with the electrical signal resulting in this code. A quick way to check it is to remove the vacuum hose going to the egr valve port and take the vehicle for a road test. If hesitation stops, it is a definite sign that the DPFE sensor is defective (make sure to plug the vacuum hose during road test).

ATS Tip:

Please read previous blog post about Ford dpfe sensor so you can locate it. You can search this blog by typing "dpfe sensor" on the top left search bar and click "search this blog".

Dash panel lights are coming on and off while driving for 2000 Grand Voyager: No codes

2006-10-23T05:27:00.000-07:00

Question:

My dash panel is driving me crazy because it would come on and off while I am driving. Also, the windshield wipers will not shut down when I used them and my power doors are acting funny by not unlocking. Finally, the blower heated motor will only work in high speed. Is this a body control module (bcm) problem?

ATS Advisor:

Yes you are correct, the bcm is going and you can check that by resetting it first by disconnecting your battery negative terminal for a few minutes and reconnect. then see if the symptoms return to confirm. If it does, check all the ground wires of the bcm as per wiring diagrams that I will send you. If no shorted wire is found, replace the bcm from the dealer. They will usually re-program it for you based on your vehicle's serial number.

ATS Tips:

Please read all previous postings on this blog about bcm.
The mileage of your dash panel is stored in your bcm which should be installed when the new one is programmed.
The blower motor needs a new resistor so it will work on all speeds.

Engine no start with check engine light for 2002 GM Silverado with 5.3L engine

2006-10-19T11:27:00.000-07:00

Question:

This truck will not start despite the fact that it has spark and injector signal. I also replaced the maf sensor and the engine compression reading for all cylinders are normal. When I scanned for codes, there are numerous codes that lead me to think that I have a computer problem.

ATS Advisor:

When you get numerous codes stored in your computer and there is spark and injector signal at the same time, this is an indication of a defective computer. However, you can actually test it by tapping the computer and wiggling the computer wiring harness to see if it would start. Remember also to drop the exhaust manifold in case the exhaust converter is plugged inside. Finally, you can check the ground and reference voltage wires of the computer terminals to see if they are within limits. If all of these fail to start the engine, replace the computer.

ATS Tip:

Before replacing the computer, contact ATS in case there is a service bulletin involved regarding the computer failure which might be under recall or warranty.

Using wiring diagram to fix the check engine light codes in your dash panel

2006-10-18T08:10:00.000-07:00

Click this link for the image!

Question:

I have this check engine light in my dash and have a code for it. My problem is I don't know how to use the wiring diagram in order to fix it. I am not a mechanic and could use your help if you can explain how to use the wiring diagram.

ATS Advisor:

Shown in the "LINK" above is a typical wiring diagram that we sent to ATS customers if they need a wiring diagram. As you can see, the path of the power and ground circuits are highlighted so you can understand how the system is working. As a member of ATS, we will explain to you the proper test and use of the wiring diagram. Once you tried it, you will know how simple it is. This way, you are not on your own trying to analyze it because it is already done for you.

ATS Tip:

Try searching this blog by typing the word "wiring diagram" in the above blogger search box (top left corner) and click "search this blog" and you will know everything about wiring diagram.

P0121 TPS sensor code for 1997 Honda Accord with 2.2L engine

2006-10-17T08:44:00.000-07:00

Question:

My vehicle is running fine but my check engine light would come on intermittently once in a while. When I scanned for codes, it was P0121 -TPS sensor "A" circuit range/performance. So I put a new sensor but the light came back after I road test the car and got the same code. Does this means I have to change the engine computer too?

ATS Adviser:

If the car is running OK, I would say your problem is probably the wiring to your TPS sensor. Since it is intermittent, what is probably happening is there is a shorted wire that would touch something while you are driving that would trigger this. To check, try probing all the wires to the tps sensor and while reading the voltage, try wiggling the wires and see if there is a change in the reading (do this with key on). If the reading changes, then you found your culprit wire.

ATS Tip:

You need a wiring diagram to do this so you can identify all the wiring colors of the tps sensor (please contact ATS).

P0121 and P0112 codes for 1999 Chrysler Sebring with 2.5L engine

2006-10-16T07:42:00.000-07:00

Question:

My car is running rough and stalls at stop lights. When I scanned for codes, I got P0121-Throttle/Pedal position sensor A circuit range/performance and P0112-Intake air temperature sensor 1 circuit low (bank 1). I checked for vacuum leak as per ATS lessons but I could not find any. Where do I start?

ATS Advisor:

Try fixing the first code first (P0121) and then reset it after you have done the repair. To check this code, measure the voltages of the TPS signal wire and if not within range, replace it. A lot of times, this sensor will fail because of its proximity with the egr valve which could be the source of the problem especially if stuck open. When it does, it will also trigger the second code. Test the egr valve by touching the egr tube if it is abnormally hot. If it is, then replace both egr valve and tps sensor.

ATS Tip:

If egr is stuck open, it will cause your air temperature to get higher.
Make sure the tps sensor ground wire does not exceed 0.250 volt.

No Start problem for 2000 Ford WindStar with 3.8L engine: No Codes

2006-10-15T15:54:00.000-07:00

Question:

My minivan quit on me yesterday and I did a quick tune up changing the spark plugs and wires including air and fuel filters and it would not start. I checked for the injector signals and they were blinking OK. My fuel pressure when tested was within limits (30-45 psi) but when I checked for spark, there is none. So I replaced the ignition module but still it won't start. My only choice left is either the ignition coil or the engine computer. How do I check it?

ATS Adviser:

You can check the ignition coil (called coil pack) by 2 methods. First, measure the resistance between the pcm terminal ignition pins 26, 52 and 78 against the coil pack pins CD-1, CD-2 and CD-3. You should get 5 ohms or less. Second, measure the resistance between ignition coil towers and you should get between 10,000-14,500 ohms. If your reading is not within this range, replace the ignition coil. The PCM is tested by measuring the ground and reference voltages as shown earlier in other blogs.

ATS Tip:

When testing the ignition coil, disconnect the inertial switch to disable the fuel pump. If you need a wiring diagram to guide you, please contact ATS.

P0441 Emission Code for 1999 Toyota Camry with 2.2L engine

2006-10-14T06:49:00.000-07:00

Question:

My check engine light is on and I got this code P0441 Evaporative System Incorrect Purge Flow after I scanned it. I checked the fuel tank cap and it was good. Where do I start?

ATS Adviser:

The most common cause of this code comes from the failure of the VSV sensor by the Charcoal Canister. What happens is the canister itself begins to break inside and creates a lot of debris which can penetrate the VSV sensor passages. When this happens, it will disrupt the sensor setting when the sensor closes or opens triggering the code. This is very common on this model and you are better off replacing the charcoal canister assembly. The canister comes complete with new sensors but you need to blow the lines to remove the unwanted charcoal particles inside.

ATS Tip:

To save money, you can remove the VSV sensor so you can open it up and clean of debris. However, the code will repeat again unless you replace the charcoal canister.

Starter not working intermittently for 1998 Toyota 4Runner: No codes

2006-10-13T07:14:00.000-07:00

Question:

These last few days my starter does not work all the time. When I first started it, all I hear is the clicking sound. After a few attempts on the ignition key, it would start and be OK the rest of the day. My battery is new and I am thinking of replacing the starter but it is expensive and I want to know if I have a cheaper alternative?

ATS Advisor:

As a matter of fact, you have a cheaper choice in repairing your starter. Most of this problem comes from worn solenoid contacts inside the starter. Instead of buying the whole starter assembly, you can buy the contact from Toyota or any electrical automotive parts store. It cost roughly under $20 and you might even get away of not removing the old starter. The labor flat rate for this is approximately 3 hours and you should be able to this in one weekend without breaking a sweat.

ATS Tip:

For wiring diagram for the starting circuit including the complete details in fixing your starter contacts, please email ATS.

Alternator won't charge for 1999 Chevy Camaro with 3.8 L engine: No engine codes

2006-10-12T08:27:00.000-07:00

Question:

My battery was going dead on me and when I checked my battery voltage at idle, it was discharging. After cleaning all the grounds and having the same result, I replaced the alternator with a rebuilt one from a local parts store. However, my battery light is still on and when I checked it, it was still discharging. I thought the rebuilt alternator was defective so I returned it and got a 2nd one installed but I got the same result. What have I done wrong?

ATS Advisor:

Some aftermarket alternator available has a regulator with 12 volts triggering signal to make it work. If you buy one from GM dealer, the triggering voltage comes from the engine computer (ecm) and only supplies 5 volt. I think this is your problem. Try using an AC Delco alternator from the dealer and you should be fine.

ATS Tip:

If you want a wiring diagram for this charging system, please contact ATS.

P0171 and P0174 lean mixture codes for 1999 Ford WindStar with 3.8L engine

2006-10-11T07:48:00.000-07:00

Question:

My dash panel light is always on for about a week and when I scanned it, 2 codes showed up: P0171 lean bank 1 and p0174 lean bank 2. I replaced both oxygen sensors and cleaned the mass air flow sensor but after resetting the codes, the light is still on? All my spark plugs were just replaced including fuel filter. Help!

ATS Advisor:

Unlike GM engines where cleaning the mass air flow sensor will give you results, on Fords you have to replace it if you get this codes. However, before doing this make sure there is no vacuum leak like the PCV hoses which are prone to cracking. To be sure, have a garage to do a smoke test on your engine to eliminate the possibility of a vacuum leak.

ATS Tip:

Every time there is a lean code, don't waste your time and change the mass air flow sensor right away if there's no vacuum leak using a vacuum gage. You should get a reading not lower than 17 inch of vacuum.

Wiper Motor works intermittently on 1999 Chevy Pick Up Truck: No engine codes

2006-10-10T08:53:00.000-07:00

Question:

My Truck's wiper motor is acting up lately, it would OK and then abruptly quit working unless I manually move the blades to shake it. I can also activate it if I play around with the ignition key (shutting it off and on a few times). Finally, I thought I heard the wiper motor buzzing when it quit on me. Do I have to replace the wiper motor?

ATS Advisor:

This problem is common with this GM truck model and most of the time; the culprit is a defective wiper module. This part is found inside the wiper motor and very easy to replace. You can test it by tapping the motor when it is not working and the motor will come alive. Once you verified this, it's a matter of removing the motor assembly and changing the module inside.

ATS Tip:

If the price difference is not much, you are better off changing the whole wiper motor assembly.

Engine no start for 1994 VW Golf with 1.8L engine: No engine code

2006-10-09T07:33:00.000-07:00

Question:

I have this car that I bought from the auction lot a month ago and would not start on me yesterday. There is no spark but I have an injector signal when I tested it with a noid light tester as per ATS. I also checked the battery side of the coil and but the tach side would not blink. Reading your articles, I now suspect the ignition module is bad but how to I check it?

ATS Advisor:

Your spark is controlled by your ignition module which connects to the fuel pump relay. Have a look at the relay if it is clicking with your fingers when you turn the key on. If bad, that relay can ground the tach signal and will cause no spark. Also, make sure there is continuity between the ecu (computer) pin 6 and the module pin 2. Finally, check the ignition module ground near the battery for corrosion and loose connection. If all of these checks OK, replace the ignition module.

ATS Tip:

Use ATS wiring diagram to trace ignition module wiring connections.

Multiple engine light codes and engine hesitates, cutting outs for 1997 Camaro with 5.7L engine

2006-10-08T04:05:00.000-07:00

Question:

My engine is hesitating and cutting out with check engine light on. Got codes for oxygen and egr which were both replaced. Despite these, the engine kept having poor pick up and stalls. I am thought cleaning the MAF sensor would fix this problem but no change either. I am at a loss and contemplating to replace the engine computer (ecm). Please help.

ATS Advisor:

If I am not mistaken, this engine came with both MAP and MAF (mass air flow) sensors and although you cleaned the MAF sensor, you may not have it tested properly. A quick way to do it is to unplug the MAF sensor and see if the problem stops. If it does, replace the MAF sensor.

ATS Tips:

When you disconnect the MAF sensor, all the loads of the engine is calculated by the ecm using the MAP signal and MAF readings will be set at default instead of the actual MAF signal.

Another indicator of a bad MAF sensor is dirt built up in the air filter which contaminates the MAF sensor wiring elements. When in doubt, replace the MAF sensor if you see a dirty air filter.

P0336 crank sensor code for 1998 Honda Civic with 1.6L engine

2006-10-07T11:37:00.000-07:00

Question:

I just bought a Honda Civic from a used car lot a month ago. Yesterday, it was cutting out and a check engine light was on. When scanned for codes, I got P0336 which is crank sensor fault. The engine also has a misfire intermittently during acceleration. Reading your blog, it seems the distributor is the culprit. However, it is very expensive from the dealer and I am not sure if the ones available from my local parts store are good enough. Suggestions?

ATS Advisor:

If you have this code P0336, the distributor is definitely toast but buying an aftermarket distributor is a bad choice. If you like, instead of buying a complete distributor assembly from the dealer, you can buy the distributor housing only. It comes with all the pick up sensors and you can use the original coil and igniter from your old distributor.

ATS Tip:

Always reset the code after performing the repairs. For details on how to overhaul the distributor, please contact ATS.

P0031 Oxygen sensor code for 2000 Dodge Ram with 5.9L engine.

2006-10-06T11:04:00.000-07:00

Question:

One of my injectors has a bad PCM driver after using the noid light tester that you recommended. I replaced it including the injector wiring harness (it was shorting out which was the original cause of the injector failure). After I replaced the PCM bought from the dealer, the misfire was gone and the engine ran good. However, my mill light was still on and has a code P0031 which was not there before. Did I get the right type of PCM from the dealer? How do I check it?

ATS Advisor:

When you buy your PCM from the dealer, they usually programmed the PCM based on your vehicle's serial number. If it is, try using the wiring diagrams and actually check the colors of the wires indicated in the PCM terminals. I have seen in some other cases where an older model was the right PCM...example: a 1999 PCM was used instead of a 2000 PCM was used on the vehicle. And you can check that by comparing the wiring colors shown in the diagram. Try this and let me know.

ATS Tip:

Before doing the above test, try calling your dealer to supply you with another PCM. The new one that you have might be defective and this happens sometimes.

P1716 No communication with PCM for 1998 Chrysler Town & Country with 3.8L engine

2006-10-05T06:39:00.000-07:00

Question:

My car has a mill light coming on and when I scanned it, I got an error code: P1716 which is not listed in obd2 codes (error code). The engine runs great but the light bothers me and I cannot check the data for my engine. Any suggestions?

ATS Advisor:

First of all, try checking the integrity of your scanner by trying a second scanner and see if you can get the same error code. The best scanner to use on this is the "BRICK" or the MT2500 Snap-On scanner which is very popular with small garages. For a small fee, any garage could do this for you unless your parts store has this type of scanner. If the same code appears, here are some common causes of this problem: Poor power and ground connections at the PCM or at the data link connector (DLC), defective instrument panel connections, bad wiring harness or defective PCM itself.

ATS Tips:

Specific testing of the PCM and other modules such as the TCM (trany control module), BCM and other accessories can be sent to you once you confirmed the code.

Measure the CCD Bus voltages at PCM pins 59 and 60 with key on, you should get 2.25 volts, if higher than this, the PCM might be defective.

No start on 1995 Honda Accord with 2.2L engine: No engine code

2006-10-04T09:59:00.000-07:00

Question:

I have no start on this car and when I checked it, I had fuel at the injectors but has no spark. I suspect my distributor is bad but it is expensive, how do I check it?

ATS Advisor:

If you check your distributor wires, check the yellow green wire. This wire comes from your distributor module called igniter. With key on, there must be 9 volts reading on it. The way it works, the module sends this signal voltage to the engine computer (ecm) and then the computer sends ground to the igniter to fire the coil. You can actually do this manually: Turn key on, disconnect the yellow green wire and briefly touch the igniter with a jumper wire from a ground connection. You should see a spark generated at the coil.

ATS Tips:

If you have less than 7 volts in the igniter, the ecm will likely not send ground to it. (bad igniter or poor ground connection).

Make sure the connection between igniter and ecm is not open (broken)

Bad spark plugs and wires usually take out the igniter.

If you can afford it, replace the ignition coil also.

Dash panel lights quit on 1999 Dodge Caravan with 3.3L engine: Scanner won't

2006-10-03T06:08:00.000-07:00

Question:

My dash panel lights that include tachometer, speedo, fuel, temperature and trany indicator just quit the other day. Last night, while driving home, I noticed the same dash panel lights flickering on and off when I turned on the headlights. There is no performance problem on the engine and it ran fine. However, when I scanned the codes today, the scanner just showed blank and not communicating with the engine computer. How do I fix this without going to the garage?

ATS Advisor:

Your instrument panel is controlled by your body control module (BCM) located under the dash on the left side of your steering column on top of the brake pedal. But a good way to check the BCM is to unplug it and see if the scanner now communicates with your engine computer (PCM) located on the left corner/fender of the engine compartment. If the BCM is defective, your scanner should come alive and function normally. Also in the BCM, you can measure the "ccd bus" voltage using ATS wiring diagram and specs so you can test for abnormal reading on its terminal pins. Finally, the dash panel unit can be taken out and checked for proper connections especially the soldered pins which can cracked and cause this problem.

ATS Tip:

If you are replacing the BCM, give the dealer the serial number of the vehicle and the mileage so they can program it on the new BCM.

Battery goes dead after parked overnight for 2000 Ford Taurus with 3.0L engine

2006-10-02T07:17:00.000-07:00

Question:

My battery goes dead after my vehicle is parked overnight. The charging rate for the alternator is good and the battery was just replaced. If I test the battery drain, it is within limits. Also, my dome lights won't work but all the fuses are OK. Some friends say that there is a battery saver for this car, how do you check it?

ATS Advisor:

Your battery saver works together with your body control module called "GEM" module. This module is active all the time and needs 45 minutes to be on (or sleep) after you shut the key off. If any of the body functions like lights, accessories, door opening are shorted, the module will be on all the time causing the drain. To check, wait for 45 minutes before testing for drain. If drain is present, get the codes for the GEM module and fix it. Your dome lights circuit should be corrected first since this can get your GEM module to be active all the time.

ATS Tip:

You need a wiring diagram for the GEM module and interior lights which can be requested from ATS if you are a member.

P0304 Code misfires on cylinder for 1999 S10 Truck with 4.3L engine

2006-10-01T09:15:00.000-07:00

Question:

My truck has a pronounced miss on idle but goes away when I rev it up. When I scanned for codes, #4 cylinder is missing. I tried relocating the spark plugs and wires of this cylinder but the code remained the same (miss at #4 cylinder). I suspect this problem is mechanical but can you guide me?

ATS Advisor:

One of the quickest ways to find if your #4 cylinder is OK is to take a compression test on all cylinders and compare it with #4. You can also hook up a vacuum gage and watch it while your engine is idling. If the needle of the vacuum gage is fluctuating and not steady, that is a sure sign of cylinder valve failure. Finally, you can measure the resistance of each injector and compare them also.

ATS Tip:

If you confirm from above that your problem is mechanical, take out the engine valve cover so you can inspect the rockers and valve train.

Instrument panel lights go out on 1999 Toyota Camry with 3.0L engine: no engine code

2006-09-30T07:26:00.000-07:00

Question:

I have an intermittent problem on my dash panel lights. It goes out from time to time and when it does, the power window also won't work. Everytime this happens, I have to change the panel fuse under the left side of the dash. There is no code when I had it scanned. How do I check this?
ATS Advisor:

If you open up your rear trunk; on the left side hinge, you will see a wiring harness that supplies ground to your lights including the power windows and dash panel. Take the wiring harness loom apart and check the wires. Most of the time, some of these wires will brake causing this problem. This is very common on these models.

ATS Tips:

If you use the ATS wiring diagram, you can see clearly the composition of that wiring harness and the colors of the wires used for grounding.

Cruise control not working on 1999 VW Passat with 1.8 engine: No engine code

2006-09-29T07:18:00.000-07:00

Question:

My cruise control quit on me 3 days ago and there are no codes. I checked all the vacuum lines and they are all fine. When I checked the power supply from the transmission control module located at the lower side of the dash by the defroster duct, there is none. How do this system works? Can I do this myself?

ATS Advisor:

If you are talking about the green red wire from the trany control module, that is supposed to be your power supply wire to your cruise control switch. However, it will only come on as soon as you put the trany in gear. It will stop when you shut off the engine or step on the brake pedal. Most of the time, this module goes because of cracking in the electrical joints in the terminals inside the module. If you call the dealer right now, they stock it all the time. You should be able to change the module yourself but don't forget to disconnect the battery when working on electric parts.

ATS Tips:

The above cruise system applies only for automatic transmission. For manual trany, power comes from the clutch switch but it does not work on the first gear.

For wiring diagrams to help you find the wire colors to all components, please contact ATS.

Code P0172 on fuel mixture for 2000 Volkswagen with 1.8 Turbocharged engines

2006-09-28T06:34:00.000-07:00

Question:

This code came up on dash P0172 system mixture too rich and as per ATS past newsletters, I changed the mass air flow sensor but the code remains. I tested it for vacuum leak but cannot find any. The engine ran fine but won't pass emission. Any suggestion?

ATS Advisor:

If this is a regular fuel injected engine, I would recommend checking the fuel regulator which could have a ruptured diaphragm. However, since this is turbo charged, it is very common for the vacuum connection going to it to leak. It's made of plastic and called a suction jet pump which is similar to a pcv valve. This part usually fails and will cause a vacuum leak when the engine is boosted by the turbo. The computer will make up for it by injecting more fuel causing the rich condition. Check and repair this leak and this should fix it.

ATS Tips:

Contact ATS if you need the vacuum diagram for these turbo vacuum lines.
The vacuum hoses are expensive and must be handled with extreme care

Oil pressure gage not working on 2000 Ford Explorer with 4.0L engine: No codes

2006-09-27T05:28:00.000-07:00

Question:

What could cause my oil pressure gage not to work momentarily when stated cold? This happens for 30-40 seconds but sometimes could last up to 1-2 minutes. However, after the engine has warmed up, the gage works great until the engine is shut down and gets cold again. Some friends said that the sending unit is defective but I need your input first.

ATS Advisor:

The normal mechanical oil pressure gage usually shoots up in reading when started cold using the regular type sending unit. However, Ford has used a different sending unit which has caused a lot of problems such as yours. Regular sending units usually work by pressure difference being monitored but this type of sending unit works like a "switch" instead. An updated sending unit is available from Ford to prevent this problem.

ATS Tip:

Make sure the engine is mechanically sound by checking the actual oil pressure with your own oil pressure gage tester. Do this before installing the new updated sending unit.

Rear power window only works in up position but not down on 1999 Malibu: No codes

2006-09-26T09:01:00.000-07:00

Question:

My rear right power window is only working when in up direction but not going down. I opened up the door panel and it seems the wires to motor are shorted because both of them have power. When I removed the motor and bench tested it, the down position would work if I reverse the ground to power supplies. Is this a switch problem? How do I check it?

ATS Advisor:

The power window works thru your master switch at the drivers door and also at the right door itself. It is done by reversing the polarity of the motor windings which is the job of the master switch. On your master switch, there are 2 wires coming out to your right door switch: light green and purple wires. When in up position the light green wire is the ground and on down, it's the purple wire. This is done thru the electronics module inside the master switch. When applying in either position and both of these wires became ground at the same time, then the master switch is defective (same if these wires are both 12 volts as in your case). However if the ground supply is reversing to either wires, then the problem is the rear door switch.

ATS Tip:

To understand this fully, contact ATS so you can get a wiring diagram describing the colors of the wires and their locations.

Rear power window only works in up position but not down on 1999 Malibu: No codes

2006-09-26T08:52:00.000-07:00

Question:

My rear right power window is only working when in up direction but not going down. I opened up the door panel and it seems the wires to motor are shorted because both of them have power. When I removed the motor and bench tested it, the down position would work if I reverse the ground to power supplies. Is this a switch problem? How do I check it?

ATS Advisor:

The power window works thru your master switch at the drivers door and also at the right door itself. It is done by reversing the polarity of the motor windings which is the job of the master switch. On your master switch, there are 2 wires coming out to your right door switch: light green and purple wires. When in up position the light green wire is the ground and on down, it's the purple wire. This is done thru the electronics module inside the master switch. When applying in either position and both of these wires became ground at the same time, then the master switch is defective (same if these wires are both 12 volts as in your case). However if the ground supply is reversing to either wires, then the problem is the door switch.

ATS Tip:

To understand this fully, contact ATS so you can get a wiring diagram describing the colors of the wires and their locations.

Rear power window only works in up position but not down on 1999 Malibu: No codes

2006-09-26T08:45:00.000-07:00

Question:

My rear right power window is only working when in up direction but not going down. I opened up the door panel and it seems the wires to motor are shorted because both of them have power. When I removed the motor and bench tested it, the down position would work if I reverse the ground to power supplies. Is this a switch problem? How do I check it?

ATS Advisor:

The power window works thru your master switch at the drivers door and also at the right door itself. It is done by reversing the polarity of the motor windings which is the job of the master switch. On your master switch, there are 2 wires coming out to your right door switch: light green and purple wires. When in up position the light green wire is the ground and on down, it's the purple wire. This is done thru the electronics module inside the master switch. When applying in either position and both of these wires became ground at the same time, then the master switch is defective (same if these wires are both 12 volts as in your case). However if the ground supply is reversing to either wires, then the problem is the door switch.

ATS Tip:

To understand this fully, contact ATS so you can get a wiring diagram describing the colors of the wires and their locations.

Fuel gage reading wrong for 1999 Ford Taurus: No codes

2006-09-25T05:45:00.000-07:00

Question:

My fuel gage does not work properly and fluctuates between 1/4 to 1/2 all the time even if the tank is full. Over the weekend, I changed the fuel sending unit inside the fuel tank but it's still the same. Some friends are telling me to change the instrument cluster but I am not sure. Can you help?

ATS Advisor:

It's good you did not follow your friends because you would be wasting your time. There is small black box behind your radio near the glove compartment and this part is usually the culprit. This part is called a flex module and connects to your fuel gage in the instrument panel and usually goes. This is a common problem and ford stock them all the time.

ATS Tip:

To get a wiring diagram so you can locate this part, please contact ATS if you are a member.

Trany won't engage in either drive or reverse for 1999 Volkswagen Passat with 1.8L engine: No codes

2006-09-24T05:10:00.000-07:00

Question:

How do you check if the trany is OK or not quickly without going to a garage?

ATS Advisor:

You can actually do this by measuring your oil level at the trany dipstick tube. All you do is compare the level when engine is off and after it has started. If the trany is OK, the level should go down at least 1/4 of an inch when engine is started. This shows that the trany pump is working inside, otherwise if no movement, trany is probably damaged and needs further testing by a trany garage.

ATS Quick Tips:

If trany has no dipstick, you can also feel the hose connection of the trany oil cooler. If oil is circulating after starting, the hose will harden as soon as the engine is started (or hook up your own oil pressure gage teed to the oil coller hose).

Be careful when going underneath your trany or contact ATS for proper procedure.

P0123 TPS code on 1998 Jeep Cherokee with 4.0L engine

2006-09-23T12:01:00.000-07:00

Question:

My check engine light code p0123 keeps coming back despite replacing these parts: tps sensor (2 times in a week), ecm (engine computer) 2 times using a used ones from salvage yard. after I drove it for a few minutes, the code always came back. Also, if I probed my TPS ground wire, I get a high battery voltage. I am losing out of options for this problem, what do I do?

ATS Adviser:

If you look at the ground wire of your tps (3rd wire and brown yellow in color), that wire is also the ground connections for other components including your ecm. You can disconnect the ecm and re-test your ground tps voltage and see if the reading drops. if not, try to unplug the horn relay in the junction box and check if the tps ground will go down. If it does, it means the horn circuit is sending voltage (shorted) tps ground via the clockspring located under the steering wheel.

ATS Tip:
For more details, get a wiring diagram from ATS.

P0400 code on egr system for 1999 Nissan Maxima with 3.0L engine.

2006-09-22T07:27:00.000-07:00

Question:

I have this P0400 EGR malfunction in this vehicle and following ATS past newsletters, I have serviced the egr valve and verified integrity of the vacuum hoses and blew the egr passages. However, after resetting the code, it came back after 3 days of driving. Did I miss anything on fixing this code? Is it possible that the ecm (engine computer) itself is no good?

ATS Adviser:

Your ecm should be good but there is a possibility that you have not really cleaned the egr passages thoroughly because this job needs the removal of the top plenum in your engine. There is a tube there that contains the egr signal to the ecm to monitor the egr system. Anytime, that passage is blocked, your ecm will store an egr fault code. You can test this by running your engine at idle and lift with your finger the egr pintle shaft of the egr valve. This should make your engine quit, otherwise, the passage itself is clogged.

ATS Tip:

While you are doing this, you can also check the integrity of the egr valve which could be stuck closed including the egr temperature sensor voltage. Finally, a weak battery can also cause this code which is very common. Please contact ATS for further details.

Heater noise on 2000 Silverado when rpm is speed up: No engine codes

2006-09-21T06:54:00.000-07:00

Question:

It is starting to get cold and my heater is making a funny noise every time I rev up the engine speed. I tried flushing the coolant system but it did not make any difference. The parts store told me that I need a new heater core but I want to run this by you before buying it.

ATS Advisor:

GM trucks like yours have this problem for a while and this is caused by a strong flow of coolant inside your heater core. To eliminate this, there is a rubber restrictor in the inlet side of the heater hose installed in it. This restrictor or orifice might have broken and must be replaced. Make sure to check this and replace if necessary.

ATS Tip:

While you are doing this, check all your hoses for connections and see that the hoses are not swelling and properly routed away from exhaust. When done, do a pressure test on the coolant to make sure every thing is tight and secure including the elimination of air in the system.(this is discussed in ATS past newsletters).

P0402 EGR code on 2001 Expedition with 4.6L engine

2006-09-20T05:08:00.000-07:00

Question:

This code P0402 -EGR flow high, came on the other day on my vehicle and when I introduced vacuum to the egr valve port at idle, the engine quit which tells me that the valve is OK. The engine seems to run OK except this nagging light so I reset the code but it came back. Is there a common fix for this code?

ATS Adviser:

There is a common fix for this and most of the time it is to replace the DPFE sensor. This sensor looks like a small box with 2 ports coming from the exhaust. The sensor is located between the valve cove and throttle body with tubes running from it. This sensor measures the exhaust back pressure when the EGR valve is activated. The passages (tubes) for this sensor can get cracked and leak to trip the code but there has been a lot of failure on the sensor itself. Also, if the tube has a build up of carbon and restrict the flow, the code can be set too. To check, measure the signal voltage of the sensor using a wiring diagram. Max reading is about 0.9 volt and any reading higher means you have to replace the sensor.

ATS Tip:

Wiring diagram is available at ATS if you are a member.

P0170 and P0173 adaptation codes on 1998 Mercedes Benz ML320 with 3.2 engines.

2006-09-19T05:11:00.000-07:00

Question:

I have these codes P0170- self adaptation out of limits right bank and P0173-self adaptation out of limits left bank and as per your ATS lessons, I checked for vacuum leak but found none. A tune up was also done just a week ago but this check engine light keeps coming back. I am out of my wits on this...how do I fix these codes without going to the dealer?

ATS Adviser:

These codes are very common on this type of vehicle especially on tthe 98-99 models and is caused by a defective air mass sensor. To check, try servicing the mass sensor as per ATS past newsletters and reset the code by touching the battery terminals for a few minutes. You can then go for a road test and if there is changed in the mill light, replace the mass sensor next time it occurs (some shops are actually changing the mass sensor right away if they see these codes).

ATS tip:

Make sure your fuel pressure is up to specification before replacing the mass sensor.
To get ATS email assistance 7 days a week, contact ATS.

2002 Dodge Caravan high beam headlight does not work : No Codes

2006-09-18T04:58:00.000-07:00

Question:

My headlight's high beam does not work intermittently from time to time. All my gages in the dash panel are OK including all the rest of the lights like fog lights and interior lights. No codes came out after scanning it and I am thinking of replacing the multi-function switch from the steering wheel but I am not sure if this is the right approach. Can you help?

ATS Adviser:

The way your lighting system works, there are 3 major lighting components namely the multifunction switch, body control module and the intelligent power module (IPM). Since the most of your lights are working except the high beam, your most likely culprit is the IPM which direct supply the power to your headlights.Using a wiring diagram, the power, ground and pci bus voltage on it can be checked and verified. If it is not within limits, replace the same.

ATS Tip:

ATS will provide the correct voltage readings for the IPM including detailed instructions on how to test the lighting circuit.

P0456 Code EVAP leak for 2001 Jeep Wrangler with 4.0L engine

2006-09-17T05:12:00.000-07:00

Question:

I have this code P0456- evaporative vacuum leak and I have changed the fuel tank cap but keeps getting this code. I also tried to check all the evaporative vacuum lines for cracks and leak but cannot see anything abnormal. How do I test this code?

ATS Adviser:

You can actually do a vacuum test on this evaporative system by activating your leak detection pump (LDP) to seal the system. All you do is supply your own ground to the LDP signal wire and disconnect the evaporative purge solenoid wires. Remember to undo also the vacuum hose supply hose going to it and install a hand held vacuum gage to the 2nd hose. This will test your LDP and all hoses if it has a vacuum leak or not.

ATS Tip:

ATS will supply you the vacuum and wiring diagram if you are an ATS member.

Don't forget to reset the code after the fix.

2000 Toyota Camry ignition key with immobilizer has no start: No codes

2006-09-16T05:31:00.000-07:00

Question:

I lost the ignition key on this car and I don't have a spare. Previous owner told me that this car's engine has an immobilizer and it needs a new ecu (engine computer) if I lost the key. Is there a way to bypass the immobilizer?

ATS Adviser:

There is no way to bypass this immobilizer and the only solution is to get a new ecu and have it programmed with a new set of keys. On a positive note, Toyota will provide you with a new ecu free of charge and you just have to call your nearest dealer to confirm this. Some dealers might refuse your request if they don't know if such practice exists and all you need to do is call Toyota head office to confirm.

ATS Tips:

Ignition immobilizer is a security system used by Toyota to enable your engine to shut down in case of theft. It does it by killing your engine injectors.

Starting 2002, Toyota can re-program your old ecu without replacing it when you lose your ignition key. Just ask them and give the car's serial number.

Battery drain on 2002 GM Silverado Truck: No Codes

2006-09-15T05:52:00.000-07:00

Question:

My battery loses charged if I leave the truck parked for over 3 days. I believe this battery is still the original one from the dealer but I am not sure because I am the 2nd owner. However, every time I boosted it, it seems OK for the rest of the day. How do I check it?

ATS Advisor:

Battery can be checked visually by reading the info on the paper glued to it and you can compare the date the battery was made against the vehicle date of manufacture. This will tell you if it comes with the truck. You can also test it by putting a voltmeter between the vehicle metal grounds against battery negative cable (remove it). With all doors shut and accessories off, the maximum reading should not exceed 0.250 volt. Higher than this means you have a drain from one of your wiring or engine computer modules. Finally, if the battery has a sight glass, make sure it is a solid green color which indicates that the battery is fully charged.

ATS Tips:

IF you have a drain, get a wiring diagram from ATS to trace the short or unplug your fuse one at a time until the drain goes away.

If you have no drain (lower than 0.250 volt), replace the battery.

You have to wait at least 45 minutes when measuring the drain. Some of this vehicle has a timer inside to automatically remove the load. Contact ATS for more detailed info.

Dash panel lights and accessories coming on and off when raining for 1998 Expedition: No Codes

2006-09-14T06:39:00.000-07:00

Question:

Why would my dash panel gages, lights and accessories devices come on and of everytime it rains? Sometimes, the blower motor would even run by itself after I removed the key. I also hear relays clicking all the time and I checked all the ground connections but I got the same result. Help!

ATS Adviser:

If your windshield had been replaced recently, chances are the windshield is leaking. This would allow rain water to drip to the fuse block and the GEM (Generic Electronic Module) module which are located below. When that happens, it will create a short in your wirings and the GEM module causing this erratic behavior. Your best strategy is to remove the windshield and re-seal it again. At the same time, replace the GEM module and the fuse block.

ATS tip:

Ask your Ford dealer to sell you an upgraded GEM module (another name for this is the BCM) and make sure it is programmed for your vehicle. For further technical assistance thru email, contact ATS.

P1143 code for 2000 Jetta with 2.0 L engine but vehicle has no performance problem?

2006-09-13T05:36:00.000-07:00

Question:

This code P1143-ecm load calculation cross check upper limit exceeded came on my scanner when the mil light appeared. There is no noticeable change in engine performance but I hate to see the mil light. This happened after my mechanic changed the mass sensor yesterday. How do I fix this?

ATS Advisor:

That code will come whenever the mass sensor that was replaced is not the correct one. Ask your mechanic to get the correct one and have it replaced again.

Tips:

To prevent ordering the wrong mass sensor, always give the engine code to match the part number of your mass sensor.

Reset the code after replacing the mass sensor.

P1128 engine lean code for 2000 Volkswagen Cabrio with 2.0L engine

2006-09-12T13:40:00.000-07:00

Question:

This vehicle has this code P1128-bank1 lean code. I have tested the engine for vacuum leak using ATS tips and no leak was found. Using my fuel pressure gage the fuel pump pressure was also checked OK. I also did a quick tune up like changing the spark plugs, wires and fuel filter to no avail. In your ATS tips, you mentioned the failure of mass sensor causing this, is this the case here?

ATS Advisor:

You are correct to suspect the mass sensor is the culprit. As a matter of fact you can call the dealer and you will find they stock it a lot. The sensor fails because of oil contamination being induced in the intake. Don't even bother cleaning it but replace it.

Tips:
Once the mass sensor is replace, reset the code by touching both batt together for a few minutes.

While you are at it, replace your pcv valve to prevent contamination.

Heater blower motor does not work on 2000 Durango: No codes

2006-09-11T08:05:00.000-07:00

Question:

My heater blower motor suddenly quit when it was turned on. However, if a direct battery power and ground are fed to it, the high speed works. There is no code when scanned but I cannot find the relay connected to it. Suggestion?

ATS Advisor:

When you jumped the power and ground supplies and the heater motor works, it means the blower motor is OK. The motor is controlled by a resistor to vary the speed. It is usually located below the blower housing and that is a common cause of failure.

TIP:

Before you replace the resistor, make sure the ground wires are secure and not corroded. Contact ATS if you need assistance.

Speedometer not working on 2000 Subaru Legacy: NO codes

2006-09-10T05:37:00.000-07:00

Question:

I have replaced the speed sensor of the speedo system located in the transaxle because the speedometer won't work. When ordering the speed sensor, I used the original equipment (OEM) from the dealer. After the replacement, the speedo works for a week but started to quit intermittently. Did I get a defective sensor? How do I know?

ATS Adviser:

If you used the wrong part, your speedo will probably won't work on day 1 but since you got it working for a week, most likely it is OK. If it is acting up again, try checking for loose connections that might cause this problem. However, if the symptom continues, consider replacing the speedo head. This head is known to fail often and if you call the dealer, they stock it all the time.

Note:

For more detailed instruction for the replacement/testing of the speedo head, please contact ATS.

P0420 and P0172 Codes for 1997 Chevy Astro with 4.3L engine

2006-09-08T22:17:00.000-07:00

Question:

This van has codes P0420-low catalytic efficiency and P0172-rich mixture bank 2. The fuel pressure is within limits and has no vacuum leak. The pcv valve was taken out and the reading to the downstream oxygen sensor did not change. Removing the dipstick tube did not reveal any blowby. What can I do before I bring this to garage?

ATS Adviser:

On this engine, you have 3 oxygen sensors. Two of them are in the exhaust manifold(upstream) and the last one is at after the catalytic converter or CAT(downstream). Try monitoring the 2 upstream sensors first by introducing vacuum leak and check the signal on the sensors. If the reading are not going down when you do this, replace the 2 upstream sensors. Reset the code after replacement and see if the down stream reading will now improve.

Note:

The 2 upstream sensors are used to monitor the engine whereas the last one is used to monitor the CAT. Contact ATS to get more help if the code remains.

P0128 thermostat code for 2002 Ford Focus with 2.0L engine

2006-09-07T16:37:00.000-07:00

Question:

This engine has a P0128 code-coolant temperature setting below thermostat-regulated parameter; engine rpm is rough every time the light is on. Do I have to change the thermostat on this?

Code Description:
This code is very common on this engine if the thermostat is stuck or partially stuck open. To check make sure the radiator cap is good or replace it if possible. If the light still shows up, replace the thermostat.

Repair Tip:

After replacing the thermostat, make sure to reset the engine code. Should the code returns, contact ATS for further assistance.

P1128 code for 1999 Jetta with 2.0L engine

2006-09-06T17:19:00.000-07:00

Question:

I got this code P1128 -long term fuel trim lean that keeps coming back even after I reset the code. An inspection and voltage measurement of the oxygen sensor looked OK and there is no vacuum leak detected. The fuel filter was also replaced but the code remained. What do I look for to fix this code?

ATS Advisor:

The most common problem for this code is the mass sensor if you believe it! Located in the air cleaner ducting, its worst enemy is poorly maintained air filter that collects dirt and contaminates the mass sensor wire elements. See ATS past newsletters for corrective action.

Repair Technique:

When checking mass sensor, check also for signs of oil contamination in the mass sensor elements that can easily corrupt the mass sensor signal. If possible, put a new one since 9 out of ten calls for the mass sensor replacement.

Chrysler Intrepid 3.5L engines with misfiring problems.

2006-09-05T10:13:00.000-07:00

Problem:

This engine misfires all the time and it happens at all speed whether the engine is cold or hot. It has direct ignition and has no spark plug wires. Instead, it has coil wire boots fed on top of each cylinder. What is the quickest way to check this misfiring?

Basic Concept:

On this type of engine, the heat build up in the engine will cause a breakdown in the coil wire boots that will arch and cause the misfire. Try unplugging the coil wire boots and have a look at the rubber insulation. If you see a brown spot, it shows the boot is arching.

Repair Strategy:

After pulling out the coil wire boots and you see even one boot arching, replace the coil wire boots as a set. (if one goes, the rest is not far behind). For more details in the repair procedures, please contact ATS.

Horn is on all the time on 2001 Dodge Truck R1500 and there are no codes.

2006-09-04T16:44:00.000-07:00

Question:

Horn will not stop but will stop if you pull the horn relay fuse or disconnect the clock spring wire in the steering wheel. Any suggestion?

Basic Theory:

As shown in ATS wiring diagram, the horn relay gets its ground starting from the horn switch that you press then thru the clock spring black red wire that activates the horn relay coil so it can send 12 volts to the horn located in the front of the vehicle. Most likely, the ground wire is shorting out making the horn come on in uncontrolled fashion.

Repair Technique:

Check the steering column black red wire that feeds the clock spring and if possible, remove the steering wheel cover to access the clock spring. If your truck has an airbag, make sure to disconnect the negative battery cable. After this, you are supposed to wait at least a minute to prevent the accidental duplication of the air bag.

P0172 code from 2000 Lexus RX 300 with 3.0L engine

2006-09-03T17:56:00.000-07:00

Question:

The check engine light in the dash is always on and a code of P0172-bank1 running rich was taken from the scanner. The oxygen sensor tested OK and there are no signs of vacuum leak when I tested it. I am now tempted to remove the engine top plenum so I can test the injectors and ignition coils. Before I do this, is there a common fix for this code?

ATS Advisor:

Whether your engine is running rich or lean, almost 95% of this engine code comes from contaminated mass sensor. Take it out and service the wire elements. This sensor usually goes in this vehicle especially if the air filter is not serviced regularly. If possible, replace the sensor and reset the code. ATS provides instructions in servicing the mass sensor including the wiring diagram.

P0300 code for 2000 Silverado with 4.8L engine

2006-09-02T11:10:00.000-07:00

Symptoms:

P0300 code-random misfire after an engine computer scan. Performed chemical tune up for top end, swap ignition coils and injectors including tune up but bank 1 cylinders still showing code of misfire. Could this be another catalytic converter problem?

Basic Concept:

It looks like this is a catalytic converter (CAT) failure if misfiring is concentrated in just one bank. Again this can be tested by a vacuum gage hooked up at the exhaust manifold of bank 1 as in previous blog.

Repair Strategy:

Another test that can be done on bank 1 CAT is to measure the voltage of the oxygen sensor located after the CAT. Normally, the signal voltage will fluctuate from 0.4 volt to 0.7 volt. If the reading is not around this range, the CAT is definitely bad. For more details in testing the CAT including the wiring diagram of the oxygen sensor wires, please contact ATS.

Code P0401 on 2000 Ford WindStar with 3.8L engine

2006-09-01T07:09:00.000-07:00

Symptoms:

Check engine light on all the time with code P0401-Insufficient EGR flow. When checking the DPFE sensor, the signal voltage was stuck whether the engine was in idle or revved up. If you apply vacuum to the EGR valve port, it will kill the engine.

Basic Concept:

The DPFE sensor signal voltage reading should change when vacuum is applied to your EGR valve port using a hand held vacuum pump. Also, take a closer look at the sensor connections for blockage or cracks that must be corrected in order for the sensor to work properly.

Repair Strategy:

Call your local Ford dealer and submit your serial (VIN) number. On some of these engine models, they will give a warranty of this DPFE sensor that has a high rate of failure. Otherwise, using a vacuum diagram supplied by ATS, double check all the vacuum connections to the DPFE before replacing it. Then reset the code before road testing the vehicle to verify the code.

P0300 code on 2002 Chevy truck 5.3L engine

2006-08-31T11:31:00.000-07:00

Symptoms:

Rough idle with code P0300 (random misfire). When spark plugs were removed, the bank 2 plugs are covered with soot. Replaced plugs and wires and it ran briefly OK but misfired again after a few minutes.

Basic Concept:

If bank 2 is acting up, I would check the restriction first in bank 2 catalytic converter. If restricted, bank 2 will not be able to breathe causing the misfiring.

Repair Technique:

The exhaust backpressure can be checked by hooking a vacuum gage on the oxygen sensor port in bank 2. Pressure reading should not exceed 3 psi. If it does, the exhaust manifold can be dropped and see if misfiring stops. Be sure to reset the code after performing the repair.

P0118 and P1128 codes on 2000 Audi with 1.8L engine

2006-08-30T07:12:00.000-07:00

Symptoms:

Hard starting after engine has warmed up including poor acceleration and rough idle. P0118 code (engine coolant temperature circuit defect) and P1128 (long term fuel trim system lean) were taken after scanning. Do I change the coolant sensor?

Basic Concept:

Whenever code P0118 appears and your thermostat is checked OK, replace the coolant sensor because it is a common problem on this model. What is happening is, the coolant sensor is stuck in flood mode causing the hard or long cranks because there is too much fuel. The other code is caused by a contaminated mass sensor that can be serviced or replaced.

Repair Strategy:

Replace the coolant sensor first to fix the first code and before servicing the mass sensor, make sure to check for vacuum leak using ATS tips or have it smoked by a garage. On some extreme case, the vacuum leak is caused by an intake manifold leak that requires a top end job. This is why you need it smoked if the 2nd code keeps coming back. When resetting the codes, remove the battery cables and touch them together for at least 15 seconds.

20002 Volkswagen Jetta with code P1128 and poor gas mileage

2006-08-29T08:59:00.001-07:00

Problem:

Check engine light is on and when scanned, code P1128 came out which stands for lean upstream oxygen sensor. Gas mileage also got worst during this time. Do I change the oxygen sensor?

Basic Concept:

When this code shows up, check for vacuum leak in all vacuum hoses and top intake gasket. The oxygen sensor can be tested manually by feeding fuel or creating a vacuum leak. If the voltage reading of the sensor changes, it means the sensor is OK; otherwise replace the sensor.However, the most common fix for this code is to check and service the mass sensor. This will usually fix the problem.

Repair Technique:

Before doing anything, service the mass sensor first and reset the code. For details in servicing the mass sensor, contact ATS. If after road testing and the code still show up, then proceed in testing the vacuum leak and the oxygen sensor itself.
Details in testing the oxygen sensor is covered in ATS including the proper way to do a vacuum leak test.