C4 Mileage/Body Control Module
Thread Starter
Burning Brakes
Joined: Sep 2002
Posts: 1,009
Likes: 62
From: Houston Tx
C4 Mileage/Body Control Module
I was having trouble starting my 1991 C4. I was receiving a diagonstic code 46 (Anti-theft system failure). After several checks were done as suggested by the GM service manual I changed the body control module. The car cranked as soon as I turned the ignition. However, I noticed the mileage read 0 on the odometer. Any ideas why the mileage would reset to 0 after the body control module was changed? Is there anyway to have the module reset the mileage to read correctly?
Also, ironically, the body control module went out about 1 month after the neutral control switch burned. I changed it and the connector and the car ran about a month. I'm thinking this switch may have somehow shorted the body control module or vice versa. Any ideas?
Also, ironically, the body control module went out about 1 month after the neutral control switch burned. I changed it and the connector and the car ran about a month. I'm thinking this switch may have somehow shorted the body control module or vice versa. Any ideas?
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
I am not sure what caused the CCM to die, but they can, and do, on occasion.
As for the mileage, this is a dealer only update. And it has to be done within 100 miles of the CCM being installed.
As for the mileage, this is a dealer only update. And it has to be done within 100 miles of the CCM being installed.
Safety Car
Joined: Feb 1999
Posts: 3,504
Likes: 4
From: Mexico Beach FL
Vetronix (maker of the Tech-1A, MasterTech, etc.) supplies the software to the dealers to download the parameters from the old CCM and install in the new CCM. Or, if unable to get the data from the old CCM, this software can modify this information.
As was said above, you have about 100 miles to do this; after that, you are locked out.
This is what the CCM has programmed into it:
1) Odometer reading
2) VIN # -- this is to prevent using another CCM to set your mileage back, because this information can be retrieved to confirm it is for your car
3) Option content of the vehicle -- like ASR/ABS, C68 climate control, etc. It is IMPORTANT to know that the CCM is the master computer and the rest are slaves. The CCM controls the communications among the computers on the serial bus. If the CCM isn't programmed with the correct option content for your vehicle, it doesn't know if the computers exist to communicate with.
4) Courtesy light time duration
Tom Piper
As was said above, you have about 100 miles to do this; after that, you are locked out.
This is what the CCM has programmed into it:
1) Odometer reading
2) VIN # -- this is to prevent using another CCM to set your mileage back, because this information can be retrieved to confirm it is for your car
3) Option content of the vehicle -- like ASR/ABS, C68 climate control, etc. It is IMPORTANT to know that the CCM is the master computer and the rest are slaves. The CCM controls the communications among the computers on the serial bus. If the CCM isn't programmed with the correct option content for your vehicle, it doesn't know if the computers exist to communicate with.
4) Courtesy light time duration
Tom Piper
1st Gear
Joined: Apr 2019
Posts: 1
Likes: 0
1995 zr1 bcm
Looking for replacement as have purchased 2 and both cant be reprogrammed. White Racing Products in Tampa sent and still have SYS lighting up and car starts without key ? Does anyone know where to get help ? and a reliable source ? Have owned car since new with 10000 original miles . Want only original but need help as everyone seems lost on this. Need my original mileage put on and safety features. my cell 818-621-8511 Aaron
Instructor
Joined: Mar 2019
Posts: 103
Likes: 11
From: Prague Czech Republic/Atlanta GA
Looking for replacement as have purchased 2 and both cant be reprogrammed. White Racing Products in Tampa sent and still have SYS lighting up and car starts without key ? Does anyone know where to get help ? and a reliable source ? Have owned car since new with 10000 original miles . Want only original but need help as everyone seems lost on this. Need my original mileage put on and safety features. my cell 818-621-8511 Aaron
An write here your experience, I am courious how it works...
