1996LT1Z28

Is there a way to find out if the PCM is dead or alive?

I have a 96 Z28, and I'm beginning to think the PCM is not working the way it should.

The fans don't come on, and I shorted pins 5&6 on the OBD2 connector to see if the computer turns on the fans.

Nothing.

The check engine light comes on, then shuts off when the car starts like normal.

I'm beginning to wonder if this thing is dead.

If it is, do I just replace it with a new one, or is this a dealer thing?

Any help advice would be appreciated.

Thanks.

shoebox

If the car runs, the computer is not dead. Just sounds like you are having some fan trouble.

1996LT1Z28

Checked both fans and sensor. All works like they should.

I'm hopeful it's just wiring.

Man I am hoping......

Injuneer

Do the fans turn on when you turn on the A/C?

Is the engine overheating, because the fans don't come on (low speed) at 226*F (stock tuning)?

How did you determine "all works like they should"? Did you provide 12V directly to the fans, bypassing the relay?

Have you scanned it for codes?

Have you checked the fusible link that supplies 12V to the fan relay load side?

Have you checked the relays?

1996LT1Z28

Replaced the one at a time. Checked them on the bench - all work normally.


Thanks for the input. I really appreciate it.

Injuneer

Are you indicating your scanner won't work? Might want to track that problem down.

The fusible links are in the wires that attach to the terminal in the red plastic "+" box near the battery. The trick is finding out which wire is for the fans:

http://shbox.com/1/fusible.jpg

1996LT1Z28

When I plug in the scanner, I can hear the fuel pump working and other things going on.

When I prompt the scanner to read the vehicle ID, I get nothing but empty spaces where the VIN# and everything else is supposed to be labeled.

I do know that the AC needs recharging, and I'm beginning to wonder if that's what the problem is all along.

When I get home tonight, I'm going to trace the wiring with my multimeter, and do a bunch of continuity checks.

If it is the computer, do I have to take the car to the dealer for a reflash, or ship the PCM off to one of those places on the net???

Injuneer......thanks for the help, I really appreciate it!

I bought this car as a dad / son project, but it's turning out to be a nightmare.

shoebox

Could it be a PCM that was previously re-programmed and maybe those items were not populated?

1996LT1Z28

That's a good question.....I don't know.