Cherokee Emission Leak

[studmanken]

OT: Shock and Amazed

Hey again. Well I had posted a question about the diagnostic codes for my 2000 Cherokee a little while ago and heeding the advice I receieved, I finally got the diagnostic code, but I can't quite seem to figure it out. The code was a P0442, which is a small emission leak. I finally got my Haynes manual at AutoZone and checked out what it had to say. Basically, it said to check the hoses and components of the EVAC system. So I did that and all the hoses looked good, minus one that seemed a little loose. Has anyone else encountered this or have any advice on what else to check? Also, I think I have to have the check engine light reset, but if I do, will the code come back on if there's still a problem? Thanks again.

 

[XJNick]

I think I have to have the check engine light reset, but if I do, will the code come back on if there's still a problem?

Yes. You cannot keep the light off unless the problem is fixed. A reset might make the light go off temporarily, but it will come on again if the problem still exists.

The code says "Evaporative Emission Control System Leak Detected ", which includes all vapor lines from engine to Charcoal (EVAP) canister, all the way back to the gas tank. Do you smell gas during or after the engine has been running? If so, you might be able to trace down the leak that way. :mrgreen:

Also, might check that the gas cap is working properly. OBD-II systems can get sort of picky about that :wink:

-Nick :!:

 

[studmanken]

I haven't smelled gas, however, I'll check after I take it out today. Yeah other people mentioned the gas cap and I made sure it was tight, but further inspection may be required. I'll also check the gas lines. Are there any specific lines that I should check or just go around checking them all?

 

[XJNick]

Its not the gas lines, but the gas vapor lines. These carry the gas vapors through the charcoal canister and into the intake where they are burned in the engine. Just start at the charcoal canister and trace the lines in both directions... you might find the leak :mrgreen:

Also, a gas cap can be bad (not hold pressure) even if it is screwed on tightly.

-Nick :!: