: What does a flashing check engine light indicate?

03-06-09, 02:17 PM

My check engine light came on a few weeks ago for a malfunctioning clutch position sensor.

While I was driving the other day, the check engine light began to flash. Then stopped. I was wondering what does the flashing indicate?? as I have never seen it flash before...in the past it was always solid....

This couldnt relate to a rich condition in the a/f ratio because the cars adjusting timing cause it thinks the clutch is depressed?


03-06-09, 04:16 PM
flashing usually means an o2 sensor or something similar...you should get it read though.

Lindsay Cadillac
03-06-09, 04:22 PM
Light Flashing -- A misfire condition has been detected. A misfire increases vehicle emissions and may damage the emission control system on your vehicle. Diagnosis and service may be required.

Generally speaking - if the light is flashing you should get it looked at...

03-06-09, 05:52 PM
thanks lindsay. It did only flash for maybe 15 seconds, and hasnt done so since. Im having it tuned tomorrow, again, but will go have the codes read first.

03-07-09, 01:23 AM
On LS engines thats a misfire. Happened when I did some custom wires for one of our trucks. Put a spark plug in just a might too tight and snapped the ceramic which caused it to misfire. Scared the hell out of me.

03-07-09, 01:45 AM
Flashing means misfire, which could come from a thousand different things.

03-07-09, 06:37 AM
EPA regulations dictate that the MIL must flash if a catalyst damaging event is occurring.
Typically this means a steady misfire event, that would dump excess fuel into the cats and destroy them.
You should be feeling a misfire when this occurs.

It should be looked at post haste.

03-07-09, 08:40 AM
Typically, the light will initially flash to draw attentention. Depending on the severity, it will remain to flash if the fault needs to be addressed immediately. A steady light means a fault has occurred but not as severe. You need to get the trouble code either through OnStar or a OBDII codereader/scanner.

03-07-09, 01:57 PM
i got it scanned.....no codes relating to this issue (I still have the clutch positioning sensor issue)

03-07-09, 02:13 PM
Can the scanner display current and history codes? Would be nice to know just in the case. :)


i got it scanned.....no codes relating to this issue (I still have the clutch positioning sensor issue)