So driving the other day, jus running around town with a clean car. I look down and notice the engine light came on. I just got fuel a few minutes earlier so I thought Mabel I didn't twist the fuel cap enough.......checked it fine......shut car off and restarted......still on. I then dropped it off at the dealership to check the codes.....was still running fine. They called back and said no codes registered, and they reset some sensors nothing came back on. Strange, and they have no explanation why the light came on......*grumble*......oh well.

 

I made 3 different trips to the dealer with a check engine light with my 09 with no definitive answer by the dealer. Finally it occured to me that if I topped of my tank to round out the price after the first click of the pump the light would come on at about 3/4 tank. The past year and a half and 15k miles have been light free for me since I stopped filling the gas after the first click.

 

Perhaps some kind of negative pressure is building up as the tank depletes after having been slightly over-filled. That could trip one of the fuel pressure sensors if it hinders the fuel flow, causing the light. If it happens again, try removing the fuel cap and replacing it, which would normalize the tank's internal pressure.

The light may stay on until reset, but if you have a hand held code reader that also resets the check engine light it's no problem. Auto Zone has them for $60, works great on my XK8.

 

Great. I will try the fuel issue and see if that works. After leaving e dealership with my light off after it was reset. I traveled about 50 miles and the dam thing came back on. Holy crap I was frustrated. I have to drive 75 miles to my dealership and then get a ride back so it's a bit of a pain. Mabel I should pick up a handheld unit to reset my light as well. Thanks for the suggestions.: )

 

I was also considering buying a OBD2/CAN code reader to check/clear the code. It would be cheaper than making the drive and diagnose it.

 

Windino-Bringing a car into service for something that is basicly a nuisance warning is an expensive and time consuming inconvience for everyone! And at $85 per reset, it's also a mini profit center for the dealerships at the customers expense. I see no excuse for it, it's pure greed.

The way most of the parameters on these sensors are set, any deviation from what is ideal performance, even for a split second, results it a light and another trip to the dealer. For example, if one spark plug misses one spark, you get the check engine light and a misfire code is registered.

I was routinely getting codes for misfire, fuel pressure drops, etc until I got my handheld reader/resetter. I used it to clear out all the old codes and reset the light a few times, and now I haven't seen another one for years, and the car has continued to perform beautifully. As a Jag should!

 

So I ended up buying a code reader and behold.......there was an O2 sensor in the cat system that was setting off. So I took the code scribbled over to my jag dealer and they read it again with a different machine and finally got the same code. The switched the sensor out with the sensor on the left side( jag procedure). They got the code again so now I need a new cat converter. Yikes. But it's ok cuz I've got a bone stock grey Toyota corolla as a loaner from them lololol. God I can't wait to get my car back!

 

Winny-Glad to hear you got your mystery solved. It's amazing what those code readers will unveil! Good thing, because my fuel tank is way below 3/4 full, and I still haven't gotten a check engine light since I filled past the auto click-off two weeks ago! So that must not have been the problem. Definatly the "cat's fault" haha.

Skid