Hi again. I suspect my ECM is shot. Since way back with the previous owner the "ABS INOP" light has been flashing yet the car brakes just fine. Now since i have purchased the car the radiator fans won't come on, period. I have changed the coolant sensor and tested the circuit all the way back to the ECM. The new sensor is good, the circuit is good. If I ground the 2 wire at the ECM the fans run.

Right now I have the fans jumped out to run whenever the igintion is on. I am close to buying a new ECM but wanted some input first. The dealer wants $255 for the ECM and Discount Auto wants $125 but you have to install your old PROM.

Suggestions?

 

What year is your car? Since this is in the LT1 section i am guessing it is at least a 93-97.

If it is a 95 or later it should have an OBD I system. Usually if the PCM is fried the car won't start.

On the 96 and 97 models i really can't advise too much. But i would say that if the PCM is bad OBD II the car would not run.

Check for wires or bad relays. Also if you can stopo by an auto Zone and they can have your car scanned for errors codes
Dave

 

It's a 1993. I tested the relays, they are all fine. The fans have power, and the wires all the way back to the ECM have good continuity.

 

Try checking/cleaning your grounds... The one on the right strut tower near the PCM and the one on the driver side, near the radiator.

 

The ABS light can be due to faulty third brake light lamps or sockets. Check for bad grounds on the fan circuit. The PCM grounds the fan control wire to energize the fan relays. Do they run with your A/C on? If the car runs good it may not be your PCM. They are very tough devices. Can you plug a scanner into it and check for codes?

 

Are you sure you are getting to the temp that the fans would come on? 226º is when they would first come on with stock programming.

The ABS has it's own computer (EBCM), so you don't need to suspect the ECM in that regard.

You can retreive codes from a 1993 by shorting pins A and B on the DLC.