Two weeks ago my spouse and i viewed a Jaguar XJR 2004 supercharge. Took it around the block, warning lights came on. The seller said it was a gas cap, and another was the parking brake. He assured us it would be fixed before we purchased. Car had 135 000 km on it. He phoned us, said it was certified, issues fixed so we drove to Niagara Falls, picked it up. I drove my car home, husband drove the Jaguar. He nearly had an accident because the driver's power mirror wasn't working. (this was Wednesday Nov. 12) Today, the check engine light came on while driving. The same gas cap sensor light came on again. We live in Ontario and the temperature here is below the freezing point. Any ideas what could be causing this?

 

The seller claiming it was a gas cap would indicate that he's had the diagnostic system scanned for "fault codes" and got back some sort of emissions leak code in response. A poorly latched gas cap or one with a bad seal CAN cause that but it is only the simplest reason, not the only one.


Before I forget the electrical items like mirrors, tilt/telescope steering column, etc., can often not be broken but instead stuck in their current positions because of years of never being moved around at all. I found that mine would start operating after a few 'gentle' manual adjustments while also using the appropriate switches. This would serve to loosen up the grease used to make the various gears and joints more easily moved. Certainly worth a try before you blow money on a motor or switch that is in fact still good.


Back to the amber light. Without having the system re-scanned there's really no way to say with certainty what the problem is. I would ask this, however. Did your husband fill the gas tank and if so did he try to squeeze as much as possible in. So much so that he pushed it past more than one automatic shut-off of the pump. If so this can lead to a false/temp light caused by a flooding of the fuel vapor recovery system to become saturated not only with recaptured fumes but in some cases raw gasoline. Once a code is set the only way to make it go away is to have the car scanned, the problem fixed (if there is one) and then the code deleted.

In the forums download area there are numerous files available and one of the best is the 6 files series that in total is the factory service manual which at almost 4,000 pages is sometimes difficult to navigate but with just a little practice becomes invaluable.

 

I need to trace down a CEL with a P0456 small vapor leak, cleared it once and stayed off for over a month until I tried clearing a code for the TPM and the P0456 came back and as long as the tank is completely full it stays off but other wise it come back in a couple of days.

 

No experience of this myself but if you google codes you can benefit from the

experience of others eg:

https://www.jaguarforums.com/forum/x...de-p0456-6423/