Diagnostic circiut question
 

Greetings all! I have a '94 Z-28, 6-speed, 140K. After much hair pulling trying to get the computer to talk to me, I finally tore the dash apart only to find that someone had removed the bulb to theservice engine soon indicator. I replaced the bulb and sure enough as soon as the car warmed up, the service engine light came on. I went to pull the codes, the light flashed for a split-second and went out, and didn't come back on. The fans came on so I know I'm in diagnostic mode, but, the computer won't talk to me. I need info on the diagnostic circuit so I can test it. Any help would be GREATLY appreciated!!

RE: Diagnostic circiut question
 

Can't flash codes on 94 and newer GM cars, you need a scanner. The 94 Camaros are OBDI and need a OBDI scanner. Some 94 cars that were built towards the end of the model run have OBDII diagnostic connectors, and in this case you will need a OBDI scanner and an adapter cord, OBDI scanner to OBDII connector. Look for details in computer section.

RE: Diagnostic circiut question
 

Another thing, some Chevy (and other GM) models get the OBDII power from the same circuit as the cigarette lighter/power socket. If a scanner ever has a problem communicating with the system, a blown fuse should be the first thing to check for. I don't know if the same is true for OBDI, but it's worth a look.

RE: Diagnostic circiut question
 

Thanks guys! I checked out the computer section as you suggested, found all the answers I was looking for. I'll find someone that can scan the codes for me. Thanks again!!