2002 XJ Sport 96,000 K
Need Help!!! I have had an incredibly presistent Emissions problem over the past several years. The message is for the well know and discussed 'check gas cap' and the DTC is alway P0455 (Large Leak). The gas cap has been replaced 3 times, every single valve (purge/canister close/tank evaporative flange etc) has been changed at least once - the purge twice. The charcoal canisters have both been replaced with new by the dealer. Every single hose within the evap system has been replaced including the part load breather and full load breather and all the hoses running from the tank and beween the cannisters and other components. The Dealer has run leak tests twice with no visible leak indicated. They appear out of ideas. Anybody out there have any thoughts. Is it possible that the ECM is defective? I love the car but this issue will put me in nut house soon. Steve

 

Have they smoke tested it? ...I would assume so, but just thought I'd ask.

 

Check all causes listed in workshop manual (for your car etc) - which include things such as electrical issues.

Also look at freeze frame data for clues.

Consider WDS (or IDS) - probably need an expert jag indy.

 

Thanks for the ideas. I assume the leak test that they ran was a smoke test but I am not 100% sure, I will ask what exactly the leak test they ran consisted of. I agree that I will probably need to find an experienced indy, since the dealer has little institutional memory for older models. The techs all are young guys and really don't have a lot of experience with vehicles more than 10 yrs out. I will follow up with them and look for an indy. I will post outcomes as they develop. Thanks all. -steve

 

Didn't know if you had it for review...

 

Found another detail I thought I had lost that's worth a check:

 

Thanks, Highhorse, as one of many steps I have taken to fix this issue I removed the gas tank and replaced the evaporative flange, fuel pump sensor, fuel pump and sender all at the same time. For quite a while I have thought that the problem was actually a leak in a hose or a malfunctioning purge or close valve, but since all of these have been replaced with new, I am now leaning toward an electrical issue possibly the purge valve to ECM drive circuit or a short circuit to ground. I am going to search for a qualified Indy to check it out since I no longer have confidence that the dealer has the expertise to work on this model. Thanks for all the ideas.

 

check the flange where the gas cap fits to the fuel tank. mine had rust on it from drain tube being blocked, hence not getting a good seal of gas cap. used a wire wheel on a drill to get rust off no more problems hope this helps jrb53

 

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