90-92 have a CCM?

[Dave P.]

2008 is a LONG time ago. I've learned a thing or two about the C4 since then.

[Joe L.]

Re: 90-92 have a CCM?

I've been reading the Helms manuals for 1993, that I borrowed from an owner. I'm fascinated by the CCM (Control Command Module) [Body Controller] and it's capabilities, complexity, and the number of things that are controlled through it. I didn't even know this system existed until I read about it two days ago.

Does the 90-92 have a CCM as well? Are the speedo and trip fields used for Diagnostics, like on the 93?

I feel understanding the CCM System is a real plus in getting a car ready for PV.

I remember taking a deduct on a 90 a long time ago for "no blue hi-beam indicator". It was such an unusual failure, I remembered it, and the car. When the Owner showed up for PV recently, I asked him how he resolved it. He said "there was no problem". I've always wondered about this...

So, my guess is that it (90) does have a CCM. The key has to be on, for the Hi-Beam indicator to work. It runs through the CCM.

Thanks,
Dave

Dave-----


Yes, all 1990 through 1996 C4 use a body controller. Each year uses a different controller. As far as I can tell, only the 1995 and 1996 controllers remain available from GM and, as it happens, these are also the most expensive of the 90-96 controllers (about $500 GM list).

These controllers perform a whole host of functions. They are also VERY difficult to access and replace. Part of this is by design since the controllers store the accumulated mileage on the vehicle.

[Joe L.]

Re: 90-92 have a CCM?

Yes, I figured that out. Seems that if you didn't 'transfer' the mileage from the original CCM to the replacement, it started out at zero. After 100 miles, it couldn't be changed. Perhaps this can be an explanation for some of the "low mileage" 90-96s out there?

Some people feel content that electronic odometers are difficult, impossible, or too expensive to 'manipulate', and therefor the indicated mileage must be correct. Doesn't seem all that hard to me. Now that I know about this, I'll begin regarding the 'low milers' with the appropriate skepticism.

Good to know the part is no longer available to do this by simple replacement.

Dave-----


They can be obtained; they just can't be obtained from GM anymore. The parts of this nature that were/are available from GM were/are always sold as "re-manufactured" and carry/carried a core charge. Actually, many of the units once available from GM were new but, officially, they were "re-manufactured". Other sources for re-manufactured units exist. For these body controllers which include accumulated mileage, I assume that the "re-manufacturing" process resets them to "0". Most of the GM Service Manuals state that the previous mileage must be entered into the replacement unit. How this can be enforced, I don't know.

In any event, it's a LOT more difficult to "modify" the mileage on cars which carry the accumulated mileage in the body computer than it is for older cars with mechanical odometers. With those, it's a "snap".

[Clem Z.]

Re: 90-92 have a CCM?

most "used car charleys" know where to get this done.