Hey guys,
I am a new member here. I own a blk 95 Z28 50k mi. Bone stock car. I am having issues with the cars CE light and cooling fans coming on at the same time. Irregardless of load temp or gear, they both come on and off together randomly. The car runs fine and does not appear to have any issues that I can see. I have a Tech 1 but it is currenlty out due to someone damaging the cord. I am in the process of getting a new one. The temp gauge in the car is steady. Could it be possible that the CTS in the pump has gone south, or is going south intermittently? Could there be a nasty air pocket in the system? Ground that has found its way out? I am going to find some time this weekend to attempt to fix it. Any ideas or suggestions would be appreciated.
Thanks

 

Its common for the PCM to turn the fans on in response to many different trouble codes. Fans coming on may have nothing to do with the CTS, air pockets or the engine running hot. The only way to tell what the problem is, is to scan it.

If you want some guesses, try and pin down the EXACT conditions under which the SES light comes on. Is it when you first start it, for the first couple minutes, then is goes out? That would most likely be the fuse for the AIR pump. If it comes on mostly under very steady cruise conditions, it may be related to the EGR system. Too many possibilities to consider. That's why scanning it is the answer.

 

Thanks injuneer
I am going to check it out further later on Friday and see what it is. I cant remember if on the late OBD1 gm's, if the ALDL can be jumped for DTC's. Anyone???

 

You can't jump the DLC on your car (93 was the last year on an LT1 Camaro). You need a scanner.

 

jd94ss:
With my '95, the original air pump (there was a dealer recall fix) failure and blown fuse meant the SES light and fan came on a minute or two after starting the car and they stayed on until the ignition was turned off ... always.
When I tried a resistor (2k ohm from my junk drawer) to disable the EGR (I couldn't get my vom probes into the EGR solenoid to read the value) the SES light did turn on and off occasionally, but never stayed on. I tried a 560 ohm resistor in the plug and the error has not returned.
(Just a thought and recounting my experiences - "your mileage may vary")

 

Thanks so much for the help guys. Well I ended up finding out what the issue was. I pulled up the ground locations and PCM wiring diagram for the car. I ended up finding that ground (i think it was G150) was screwed up. After looking at all the paperwork the old man gave me. It seemed that before he had parked the car it was in the dealer for a recall on the cyl heads due to them leaking, and they were replaced. Well I found the ground's on the DS head to be intermittently making contact. Also I found the air pump fuse blown as well. I crimped, soldered and heat wrapped all the grounds. Checked with my fluke and everything was kosher there. Also replaced the air pump fuse. Once that was all said and done. She fired up no CE light no fans on and off. And verified proper working condintion of the air pumps wiring along with both the fans. Took the car out on a pretty long drive stop and go and heat soaked it. Problem has not come back.
Thank you guys so much for your help and info. I really really do appreciate it.
Thanks again,
Johnny