I have a warning light saying to check my fuel cap. I tightened the cap again & the light is still on. I took off the cap completely; tightened again and still the warning persists. Anyone else run into this?

 

Yes there was a similar post on this forum withing the last six months.

You can take the gas cap to one of those places that does emissions testing, and they can put it on a device the determines if it leaks.........or not.

Part of the emissions of modern cars is for the ECU to pull a vacuum on the fuel tank and see how long the tank will hold a vacuum. If you have a leaking gas cap or a leak from another source like a fill line, then the car will fail the test and you get the warning you just got.

It 'ain't' always the gas cap leaking.

https://www.jaguarforums.com/forum/x...warning-88860/

 

Also, the indicator does not go off immediately...sometimes it takes a few drive cycles...

 

Same thing happened to me recently. The first time, the light came on with no CE light. Bought a new cap for $35. from the dealer and all was good...for two weeks. The second time, it came on and so did the CE light. A friend put his OBD reader on and the code was P442 "small emissions leak." He cleared the code and warning lights went out. That lasted a week and the warning and CE light came on again.

Dealer wants $250. just to do a smoke test with no assurance the leak would be found, then, whatever $$ to fix it.

So, I bought a basic OBD reader and cleared the code and lights again three weeks ago and so far no issues. Is this the smartest way to address the issue?
Probably not but I'll live with it for now.

Best regards,

 

Hey Tom - when it comes time to get your emissions inspected you will not pass if you have reset your codes within a certain number of drive cycles.

Something to consider...

 

A little history: Two yrs ago I bought a van that turned out to have this fault. After changing the cap and tightening what lines I could access, I ended up dropping the fuel tank to find that the vent line that runs from the top of that tank to close to where the fill cap is, was loose on top of the tank. Fixed same and no codes since.

When removing the tank there were tell tale signs that I was not the first person to remove the tank. Signs like hose clamps missing where there should have been a clamp.

Hope this tale does not strike fear in your heart.

Memory also reminds me that on that particular car, the TEST would only be performed if the tank was b/t 15% and 85% full. I don't know if that is the case with Jaguars or not. Might account for the long time b/t the code being not showing.

And yeah, you might erase the code, but until the 'drive cycle' for that particular item is finished, the code will be stored in the coumputer and the emissions tech Will see its presence. Not good. Some scanners when hooked up to the car will show a amber light indicating that there is an erased code that has not yet gone through the 'drive cycle' to permanently erase it.

Here's what happens on a Chevy Venture when that code is encountered: http://www.my-chevy-venture.com/P0442-dtc-details.html

 

What first alerted me that I might have a problem was that the guy at the emissions station took four tries before it passed. Got my 20 bucks worth out of that one!