: Flashing CEL



mstrjon32
03-11-12, 01:17 PM
I was driving home today, doing about 110 mph and looked down and saw the CEL flashing. Pulled over and it was still flashing, shut the engine off, checked all the connectors at the ignition coils, started it back up and it was fine. Never felt like it was missing or had any other problems. Got back on the road, and it didn't come back. I was driving 100+ mph for 20-30 miles prior to that with no issues. Plugged in the scanner when I got home and there are no codes.

Was this a fluke, or what?

darkman
03-11-12, 02:53 PM
Any misfire condition that is sufficient to cause overheating of the catalytic converters can cause the check engine light to flash. See attached.

06BlackV
03-13-12, 08:56 PM
Any misfire condition that is sufficient to cause overheating of the catalytic converters can cause the check engine light to flash. See attached.

How would you go about diagnosing the origin of the misfire?

darkman
03-13-12, 09:17 PM
How would you go about diagnosing the origin of the misfire?

If the flashing CEL does not recurr and no code sets it may have been a temporary condition that no longer exists.

If it comes back on a permanent basis a specific misfire code may set which indicates more specifically what the problem might be.


A shop with a GM TechII scanner can check to see if the computer is storing and "history" DTCs.