Started yesterday - my check engine light (not red) remains on the entire time the car is running. No noticeable performance reduction. I hooked the car to an AutoZone diagnostic scanner and got no fault code. (Prior experience is that these scanners are of limited utility on my car.)

So, check engine light on, but getting no fault code.

2001 XJ8, 267,000 miles.

Any thoughts on what it might be? (No "old age" jokes please!)

THANKS

 

THEORETICALLY, what you describe shouldn't occur. Thoughts? Try a different scanner.

 

Yep, need a better (working) OBD tool.

Or just possibly you have a weird dash fault never posted before which puts the MIL on all the time. I guess eventually this must happen to someONE.

 

Not related, but an XJ8 I bought had a MIL that never came on although both O2 sensors were faulty. I stripped out the inst cluster and found the MIL LED had been removed, so it never lit. With all the other lights that come on during the ignition check and then go out I never noticed it until I plugged in an OBD reader and found the Sensor faults that should have brought on the MIL.
Bill W

 

Most scanners indicate whether the CEL is on or off and have a function to turn the CEL off. Have the auto zone guy try again.