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

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.