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Small Evap Leak, and ac Switching

Old 06-12-2019, 12:28 AM
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Year: 2003
Model: Grand Cherokee (WJ)
Engine: 4.0L
Default Small Evap Leak, and ac Switching

Alright I recently got my new WJ and aside from one of the previous owners weekend projects being an abysmal paint job on it, its damn near flawless.
Accept a few weeks later now I've got a minor check engine code, the AC and the cruse control was intermittent, and the ac blower is staying on when the blend door dial is set to off, but turning off when set to defrost.
The intermittent ac/cruse control was a simple fix I checked the line from the side of the intake and it wasn't even connected so I slipped it over the barb and that was a simple fix.
The check engine code is a P0442 "small evap leak" the gas cap is in good condition and tightens down just fine, and under the hood all the evap lines look brand new, so some ideas as to what the issue could be would be appreciated.
As for the blower staying on, I am at a total loss as to what the issue could be. I pulled the panel out of the dash and played with it a little to no avail the switching for power os on the opposite positions and that it, all the air goes to the right place otherwise.
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Old 06-15-2019, 09:23 PM
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Year: 2000 XJ Sport & WJ Laredo
Model: Grand Cherokee (WJ)
Engine: 4.0L
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Try putting Vasoline around the sealing surface of the cap and clear the code. Even though to looks good, it may not be sealing. This will eliminate it as the culprit. If the code comes back, look elsewhere. I had the same issue with my 2000 WJ and after smoke testing it, we couldn't find the leak. It turns out it was the schreader valve in the test port! You can't buy just the test port at a dealer, you have to buy the entire hose assembly! I went to the junkyard, got 3 for $3, and the first one worked. That's the "T" fitting with the green cap on it. Now I have 2 spares, if I can ever find them, LOL! That tire valve type thing only seals 1 psi and it dries out and leaks. We found it by injecting the smoke at another place. Good luck in your "hunt."

BTW, it's the mode switch that directs air to the various places. It's a vacuum control, but shuts off the low blower as well. The blend door controls the heater output temp. It's a stepper motor that moves the door and stops in different places controlling how much air comes thru the core.

Last edited by dave1123; 06-15-2019 at 09:26 PM.
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