Sorry if this has been answered a bazillion times, but I cant currently search the forums since the feature is disabled.
Anyhow, Yesterday I jumped into my Jeep (2001 Cherokee Limited, 46,400 miles) and got almost out of my development and the check engine light came on. Went to Walmart and picked up an OBD-II scan tool today and found the PO442 Code stored and it was the only code in the system. Looking at this site: [link]www.obd-codes.com[/link] I get the following:
P0442 OBD-II Trouble Code
Evaporative Emission Control System Leak Detected (small leak)
What does that mean?
This indicates a fuel vapor leak in the EVAP control system. It means a very small leak has been detected. In fact, the leak can be from a hole as small as 0.04" in diameter. The (EVAP) emission control system prevents the escape of fuel vapors from a vehicle's fuel system. Fuel vapors are routed by hoses to a charcoal canister for storage. Later, when the engine is running a purge control valve opens allowing intake vacuum to siphon the fuel vapors into the engine.
You likely won't notice any drivability problems.
A code P0442 most likely means one or more of the following has happened:
* A loose or improperly affixed gas cap
* A non-conforming gas cap (i.e. not factory/original brand)
* A small leak/hole in a fuel vapor hose/tube
* Other small leak in EVAP system
* Faulty vent o-ring seal
With a P0442, the most common repair is to:
* Remove and reinstall the gas cap, clear the codes, and drive for a day and see if the codes come back.
* Otherwise, replace the gas cap, or
* Inspect the EVAP system for cuts/holes in tubes/hoses
I cleared the code and reinstalled the gas cap. I can't tell if it was not on right or not, but I am at a 1/4 tank of a recent fill up on Monday and it ran fine the whole time with no problems. I am really hoping it is just the fuel cap, but wondered if anything besides the above could trigger this code. I guess I am looking for previous experience with this. I don't understand how I can go almost a whole tank of gas before the MIL triggers. I thought I read somewhere that the fault codes must be present for 3 consecutive trips before it illuminates the MIL/CEL, but now I can't find the site. Anyone know if thats true? I know I filled it up on the way home from Ocean City. We stopped at a WaWa's for a potty break and then got home and unloaded the Jeep. I then took said Jeep to pick up our dogs. The next day I went to pick up my son at football practice and Jeep was still fine. It wasn't until yesterday, no more than a hundred feet from my driveway the light came on.