Need New Body Control Module

[staticuky]

My body control module is bad on my 03 z71. I am getting voltage into it but not out of it. I know you are supposed to flash the chip on a new BCM with all of your vehicle details, but what are the consequences of just putting a BCM from another totaled 03 z71 in? Will the car start and what issues are expected if any?

 

[03YukonNH]

The car won't start. It will crank but not start and all the antitheft stuff comes on for the radio. I did it recently when I bought a used BCM just to see what it did. When you put the old one back in the truck will start right up again. A flash for the BCM will cost you 1 hour labor at the dealer. Approximately $90 and no one else but them will have that TechII scanner so your hands are tied.

 

[staticuky]

Thats what I was thinking would happen. Can a used BCM be re-flashed? Or is it a one and done kind of deal?

 

[03YukonNH]

Yes, they can be reflashed. There is some code that needs to go into the Tech II scanner based on your VIN number. I paid $50 for a used BCM and $90 labor for it to be reflashed.

My f'ing alarm kept going off in the middle of the night because it thought the rear gate was being opened. There was a problem inside the BCM for the rear gate circuit. $140 was well worth the peace of mind knowing the alarm won't randomly go off and the interior lights won't randomly come on.

 

[OmarR]

There is a procedure for mating the BCM to the PCM, and that will at least get your truck to start. The radio will still be theftlocked, and will need to be un-locked with someone with a Tech 2 programmer, but at least your truck will be driveable.

I will look it up in my shop manual when I get home and post it up later tonight.

 

[OmarR]

30 Minute Learn Procedure:

1. Turn ON the ignition, with the engine OFF.
2. Attempt to start the engine, then release the key to ON, vehicle will not start.
3. Observe the SECURITY telltale, after aproximately 10 minutes the telltale will turn OFF.
4. Turn OFF the ignition, and wait 5 seconds.
5. Repeat steps 1-4 two more times for a total of 3 cycles/30 minutes, the vehicle is now ready to relearn the PASSLOCK sensor Data Code and/or passwords on the next ignition switch transition from OFF to CRANK.

Important:
The vehicle learns the PASSLOCK Sensor Data Code and/or password on the next ignition switch transition from OFF to CRANK. You must turn the ignition OFF before attempting to start the vehicle.

6. Start the engine. The vehicle has now learned the Passlock Sensor Data Code and/or password.

7. With a scan tool (like the ones you buy at autozone) clear any DTC's (trouble codes) if needed. DTC's will self clear after 100 ignition cycles.

 

[ThierryC78]

Thanks for describing the procedure, but is it to allow a BCM with a different VIN to work on a truck or to remove the theftlock from the radio ??

Also if one was to use an after-market radio, there should'nt be any problem with the theftlock should it ?

 

[OmarR]

to allow a BCM with a different VIN to work on a truck

This.

The OEM radio will still be theftlocked.

Yes, it will not be a problem with an aftermarket radio.

 

[bmil]

I know this is an old post, but it is my issue exactly. I have a new BCM and followed the instructions posted by OmarR above. Step 1 - OK. Step 2 - Car starts very briefly and radio come on very briefly then both shut off as expected. Display shows "unknown driver" etc. The "telltail" , what I understand to be the small blinking light at the top left of the radio, blinks ~ once each 2.5 to 3 seconds. I waited 10 minutes, still blinking, 11 minutes still blinking, 15 minuted still blinking. My hope was to get the new BCM in place before taking it to the dealer to get programmed. What have I not understood correctly? My only issue is the "rear access open" message. All other doors actuate/display correctly, the alarm does not go off if it happens when parked, and all the other settings for both sets of keys, radio, etc. stay intact. The problem seems to be temperature related as when it got cooler out, I did not get the "rear access open" message but it returned when it warmed up today. Any and all help will be appreciated. It's not pleasant to have all the lights go on at night on my way to work! I have all the bulbs pulled for now. By the way, I have eliminated the possibility of the rear wiring to be the issue. It all ohms out correctly. I have clipped the black/red lead at the module to eliminate any question. Still have "rear access open".

 

[OmarR]

The yellow security light is in the cluster, not the radio.