Hi, the other day, my check engine light came on while I was driving. So everytime I go to drive my car, it stays on. I tried to use my diagnostic feature under my dash, but nothing works. I put a jumper wire to the A & B terminals to see if any codes will flash but the light just stays on. It won't flash at all. Whats the problem? Im guessing something is wrong with the diagnostic system or something because it aint working at all. If the diagnostic system aint working, how would I go about fixing it?

86 Trans Am

 

Does it come on immediately when you start up your engine? Also, I'm not sure if you're using the paperclip method...but goto WalMart and they have SES decoders for like 20 bucks. Ps. Where in michigan are you

 

Yes, it turns on when I start the engine up. I tried resetting but still the light stays on when I try to troubleshoot it. Nothing will flash. I live in Port Huron, MI.

 

Did you check to see if the SES lamp flashes once briefly when you first turn on the ignition?

 

I know this is a really old thread, but I'm having some problems with my check engine light also.. it's on whenever the car is running and turns off when I shut the car off, but when I ground the terminals with a paperclip it doesn't give me any codes. Like Vader was mentioning, it flashes once briefly when I turn the ignition on, but it never flashes the code 12 or anything else either. What would cause that to happen?

 

 

With the ECM disconnected, the SES light came on and stayed on when I turned the key to run. After plugging the ECM back in, I turned the key back to run and it still is only giving one brief flash. According to my Haynes manual, its supposed to give a code 12, which is basically 3 flashes, if the diagnostic system is working. Any ideas about what else I should check?

 

 

With the fuse removed, the light shuts off..