the check gas cap message came on while driving, so i stopped and found gas cap secured ok. I took it off and put it back and continued on my journey, then the engine warning light came on???? car is running perfect, but the yellow engine picture is on speedo, what gives??? I am a new owner, 2001 XK8 w/ 33000 miles. HELP!!!

 

The 'check gas cap message' on a 2001. Do you mean the low fuel level indicator that comes on when you're down to 10 litres (a little over 2.5 gallons)?

If the Check Engine light is on, get the codes read or it's just guesswork.

Graham

 

the message read "Check Gas Cap" and how do you get the codes??

 

The check gas cap is displayed when there is a leak in the evaporate system for the fuel tank. The check gas cap message is displayed because it is considered the most common fault by the factory. if you check codes there will be a evap leak code set, some common things are the canister close valve, leaking carbon canisters or leaking tube between the canisters, or leaking purge valve by the throttle. to check properly the canister close valve has to be commanded shut by a scanner or ids

 

Hit post by accident.

Then use a evap smoke machine or pressure tester and the search for the leak. sometimes can be hard to find.

 

If you haven't got access to a code reader then Autozone or similar will read them for you.

Write down exactly what the code or codes are and post them here.

Graham

 

It also doesn't preclude that the gas cap itself may be bad. Had tons of those at various dealers.

 

Thanks guys, I will have the codes checked and post them.

 

I had the codes checked and they read:

P0455 : EVAP EMISSION CONTROL SYSTEM LEAK (large)

P1000 : MANF CNTRL FUEL&AIR METERING, AUXILIARY EMISSION CONTROLS


I erased the codes, and the engine warning picture. I was driving again and the
"Check Gas Cap" alert popped up. I turned of the car and removed the gas cap, I tapped the gas cap against a wall and re-installed it. I have not had a problem yet.
I guess I need a new gas cap?

 

Looks to be a good diagnosis.

P1000 : System checks not completed since last memory clear
P0455 : Evap (system) leak detected - large

The first P1000 is normal and will appear every time the codes are cleared until you've driven sufficent miles (or deliberately done 'drive cycles') to complete on-board monitoring tests. At this point it changes to P1111

P0455 possible causes range from the simple Fuel Cap off or Fuel Cap Seal defective through EVAP component physical damage or harness faults. The wall treatment points to the simplest - it's looking like the Cap.

Graham

 

the evap system is one of those systems that just needs maintenance as the car ages, the canister close valve will stick open/close due to rust falling into it from the vent tube which is metal...its gonna happen. Gas cap is cheap to see if it fixes it, but if I were a wagering enthusiast, i'd put a chip or two on the CCV - vent tube combo. let us know how it goes please!