After 2 months of trying to determine what caused my 1996 LT4 interior lights/systems to just completely die, I diagnosed as a faulty CCM. CCM's are no longer built and GM does not offer for sale any longer, so I purchased a used one off of ebay, knowing I would have to get it reprogrammed. I installed it and it did fix the problem as it relates to all the systems working; I just can't start the car as the VATS system is preventing it from starting. But, the LCD and all other systems that were dead are now lit up and ready to go.

My understanding is that the CCM must be reprogrammed by a Tech1A.

My questions are this:
1.When getting the replacement CCM programmed, can the VATS code be reprogrammed into it? If so, can the mileage and VATS code be downloaded from the faulty CCM and input into the replacement CCM? (I don't know the VATS code, but I can determine that by checking the resistance on the key)

2.When programming the CCM, does the Tech1a plug into the OBD port or is it reprogrammed by plugging into the CCM directly, as the CCM has 2 plug-in ports? Can the reprogramming be done without the car or does the CCM need to be plugged into the car?

3.Does the CCM store the VATS code? If so, the dilemma I face is that I don't know the VATS code to the replacement CCM and although I can determine my key resistance, would I have to replace the ignition switch with a key code that matches the replacement CCM? (I have watched a video online as to how to fairly easily bypass the VATS system, but my key does not match the replacement CCM.) Don't know what to do or can the CCM be programmed with my key?

4.I have read that a CCM must be reprogrammed within 100 miles; does this apply to a used CCM or does that refer to one that has been rebuilt and zeroed out? I would like to input the correct mileage into the replacement CCM as the replacement CCM has more miles on it than the correct mileage of my car.

5.Last but not least, and the most important question: Where can I find someone that can program this thing???? I checked the Chevrolet dealership and a couple of other mechanics in town, and they don't even know what a CCM is. So, I don't want to let them touch it if they don't even know what it is or what it does.

6.Is this something that is as easy as plugging in a Tech 1A, and entering mileage, options, etc? If so, maybe I should just find a used Tech 1A with the proper software? Maybe the problem lies in that nobody has a Tech1A?
Any help would be greatly appreciated.

Thanks,
Alan

Hi Alan

1994, 95 and 96 were odd balls as GM was converting from OBD-I to OBD-II
Thus the CCMs were also odd as in 1997 GM went full bore OBD-II as EPA required
All changed as odd years used PCM and CCM where ECM used a E-prom to store engine calibration, pre 1994
ECM then was connect to CCM via low speed network as CCM is the commander of the network

Both exchange information via the network where common connection to both are via the ADLC under the dash

This means tools do connection to the ADLC and talk over the network, so yes the older Tech-1 was used by GM tech's to do updates, etc

If the CCM you have now is working OK for HVAC, seats, radio, etc I suggest solving this as I do for my customers is turn VATS OFF in the PCM tune and forget about finding someone who
can talk to the CCM as VATS could fail later on and your back to a problem again

Your better off as this way if the ign switch or key pellet goes bad or even VATs fails with it turned off in the PCM all that VATS functions are ignored.

Your 1996 uses a PCM, difference is it has flash memory and not a E-prom as ECM did.

I cannot recall but you might want to look to see if shunting certain pins of the ADLC is used causes PCM and CCM to resync the security seed

Hi Alan...May I add a bit here? Confusion may set in and correct me if Im wrong but GM calls the CCM a BCM or body control module. These BCM's are used from 1990 to 1996, and will fit these years. GM part numbers include:
1996- 1995: 88961152, 16320561, 16230686, 1994: 88999217,16212971, 16157364, 1993 1992: 88999216, 16193458, 16159188, 1991: 88999215, 16155502, 1990: 88999228, 16146688, 16132128. Salvage yards tell you the BCM fit those years above and can be interchanged, HOWEVER as you suspected and stated some will tell you "additional programming needed" and the list above is not complete. I found this number for 94 to 96 as well 16208004. Here comes the tricky part, as you stated you cannot find a "new CCM BCM" ....AC/ Delco does have a "reman" line of these for those that have access to their product lines. And of course they "updated" the part numbers to add to more confusion. I believe team ZR1 has a programming tread here. BCM's are pesky little computers, my 2017 KW has them, Volvo, Peterbilts you name it. Trouble is as you stated most Dealers do not have the help now days to figure all this out. Tech 1 scan tools can be found on ebay. Personally I had a problem with a upgrade radio installation, i ended up bypassing the BCM with no issues. Tech 1 scan tools are still available: OEM Tools.com
87 Eastman Street
2nd Floor
Easton, MA 02375
United States
Phone Number: 1-86-OEMTOOLS
Fax Number: 1-508-238-5219
Hours 8:30AM-5:00PM Eastern Standard Time .....I hope all this helps,