Monday, May 29, 2006

Check engine light obd2 code P0401 on 1998 Honda Accord


After the engine is started, check engine light is on and when scanned, code P0401 showed up. This code means insufficient egr flow. How do you test it?

Basic Concept:

First reset the ecm to remove the code and make sure it is not an intermittent code. Take the vehicle for road test until warmed up. Then decelerate the vehicle from 55 MPH at least 5 seconds and determine if the check engine light stays. If it does, scan for codes and see if obd2 code P0401 returns.

To fix this, remove the intake plenum by taking off all the plastic covers of the plenum. Unbolt the throttle body by removing the two nuts and two bolts. Then unbolt the intake plenum and disconnect all the hoses and electrical connectors at the rear. The throttle body can be tapped with a mallet where it connects to the plenum and it should come loose. The plenum can then be lifted and pulled out from the throttle body. Turn it over on a bench and use a 8 mm bit to drill out the EGR passage near the front of the plenum. All carbon deposit and debris must be removed and cleared. Once cleaned, everything can then be assembled using new gaskets. Reset the code and that should be it.


For exact location of the exhaust ports to be cleaned, get hold of Honda Accord service manual or contact ATS.

Honda dealer should warranty this but phone them first.


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