swapping the bcm

electromag8 · February 23, 2004

bought a bcm on ebay off of a 2000 silverado for my 99 sierra. Wanted this for the auto unlock feature. my problem is that the truck runs for about two seconds, then shuts off. I've seacrhed about this topic and have read about a "learning" procedure but haven't found it. Can anyone help? Thanking you in advance...

Shaners · February 24, 2004

This probably isn't 100% correct but here goes...

It has something to do with turning the truck to the run position and leaving it there until the "security light goes out (about 10 minutes). Then I think you try to start the truck (not sure about that part). Then do it over again... Then do it one more time...

After that the truck should start.

It goes something like that.

From the symptoms you describe, this will fix your problem.

linda · February 24, 2004

doesnt the BCM have to be programmed for your VIN? I am pretty sure its a security measure. the BCM can be programmed with the tech2. I had mine reprogrammed because i removed my camper mirrors and wanted the features that came with the power folding mirrors. Worked like a charm. Have it reprogrammed....you should be fine.

electromag8 · February 24, 2004

Thanks shaners, thats the best I have to go by now, so I will give it a try. If it doesn't work, at least I have a company truck to drive to work tomorrow!!! Appreciate the help. I'll let you know how I make out.

Import Hater · February 24, 2004

The procedure Shaners just gave you is the Passlock relearn procedure. The value being sent to the BCM from the ignition switch doesn't match so it thinks it's being tampered with and shuts down. It'd be the same as if you replaced the lock cylinder.

Rob

electromag8 · February 24, 2004

Tried the aforementioned "learning" method...no luck. Put my old bcm back in now truck won't run for more than 2 seconds with that one either. Guess now I am really SOL. Will probably have to call the dealer up the street. The last time I went to them they said GM recommends that you replace the engine and transmission after 100,000 miles. So I can see this will be a real joy!!! Thanks for the help anyway .

Butch 02 Denali · February 24, 2004

The password learn procedure must be performed if passlock sensor, body control module (BCM), powertrain control module (PCM) or vehicle control module (VCM) has been replaced. Make sure the battery is fully charged.

Turn ignition from OFF to CRANK, allowing the vehicle to try and start. The vehicle will start and stall. Leave the ignition on and observe the "Security" indicator on the instrument panel. When the security indicator turns off (10 minutes), turn the ignition key off and wait 10 seconds. Repeat the procedure 3 more times. The new "password" is learned on the next start attempt.

Perform this procedure EXACTLY, and your problems are solved!

Hope you see this before you spend money towing to the dealers!

Butch 02 Sierra Denali