replacing BCM
Thread Starter
Intermediate
Joined: Oct 2006
Posts: 36
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replacing BCM
I just purchased a new BCM. I know it will need to be programed at the dealer with a scan tool. My question is, can I install the new BCM and wiil the car start so it can be driven to the dealer for programing?
Safety Car
Joined: Aug 2000
Posts: 4,933
Likes: 30
From: San Rafael CA
The BCM then sends a "password" to the PCM telling the PCM that it's OK for the car to be driven (the engine will start without the password .. but if the PCM doesn't get a valid password it will kill the engine when you try to drive the car).
Each time the car is started and the PCM and BCM match on the password, they then agee on a "new" password to be used the next time the car is started. The chances that a "new" BCM and your current PCM will agree on the password are somewhere between slim to none (with emphasis on none).
There are other interactions as well, for instance the SDM (controls the air bags) also communicates with the BCM at start up and if they don't agree on the "PROM ID" then the SDM sets a B1001 DTC.
HTH
Last edited by BlackZ06; Dec 13, 2006 at 05:26 PM.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Man,,,you are SOOOOOO correct!! 
VERY good explanation!
There is however an alternative BCM/PCM sync procedure that will get you to the dealer but for the life of me I CAN NOT locate it!!
Someone will most likely pipe in and provide it! BC
Racer
Joined: Apr 2006
Posts: 397
Likes: 3
