A few months ago I started getting a check engine light on my 04 Jeep Grand Cherokee related to EVAP leak. When I talked to the Jeep tech at David O'Neal and the Advanced auto guy, they both told me it was most likely just due to a loose gas cap or the seal/valve in the gas cap was broken and I should start troubleshooting by replacing the cap. I replaced it probably 2 months ago and have reset the check engine light multiple times but it alway comes back on within 3-4 days.

Also, whenever I start my car (especially when its cold out) I can hear a faint constant clicking sound coming from the lower left rear qtr panel where the canister sits. Am I most likely going to have to replace the canister? Anybody on here have any experience with EVAP related stuff on a Jeep or am I going to have to take it to the dealership and get robbed.

codes:
P0455 - EVAP Emission Control System Leak (LARGE)
P0442 - EVAP Emission Control System Leak (SMALL)

Thanks.

1/31/2009 5:14:13 PM

start by checking all your lines for cracks or broken fittings

if all looks good, then with the engine off, put 1 psi regulated air pressure on the test port under the hood and listen for leaks, if you can hear it and cant figure out exactly what id leaking, light a ciggarette and hold it around the fittings and you'll see the smoke blow away from the leak

1/31/2009 5:20:39 PM

ok so who's got a pump and wants to find this leak for me?

2/1/2009 5:05:46 PM

I don't think there is anyone excited about chasing evap leaks.

2/1/2009 6:29:23 PM

definitely worth taking it to a shop if checking the obvious stuff doesn't work.

[Edited on February 2, 2009 at 1:23 AM. Reason : I would honestly consider the stealership because they have OEM tools]

2/2/2009 1:20:07 AM