USAFPILOT

Well after enough frustration with batteries etc. I sent the car up to the local dealer for some diagnostics. They reported the CCM has failed and needs to be replaced. Rather than paying 2000.00 to have the dash torn out by them I elected to have the car sent back to my house and I will do it.

Someone plz tell me this in't a mistake, my towing bill is going to be enough already.

Is there anyone who has done this repair themselves? Can you give me some instruction. I have the GM manual so I'll be follwing it to the T but it leaves some things out.

Also...where can I get a CCM? Central Control Module. They said they didn't know if they could even get one.

The car is a 1994 ZR1.

-=Jeff=-

Well the CCM HAS to be programmed by the Dealer, as all the mileage and info (bose, Electronic a/c, etc) need to be programmed in the new CCM. when I did my 91 dash conversion on my 89 I was lucky to find a dealer (local club member) that was willing to program the CCM for me..

they will need your old CCM and New one to transfer the data, or at least the mileage.

BEFORE it is towed, be sure they will program it for you, if not, unfortunately they will need to do it..

Good Luck

zr1fred

The CCm is on the firewall behind the airbag module, and the radio. It's a pain to change, but not as bad as heater core. As far as I know, they are still available from GM ( I think 94-96 is the same), but you'll need to take it in to GM or somewhere with a (?)TECH II and have the mileage and serial data entered. Last time I checked, the module was $250 or so, and the "flashing" or entering data was $250 (these are approx).

corvette1989bham

The ccm rarely goes bad and is one of THE most unneeded parts replacement on a c4. If you PM me,I can help you. I am in Alabama if nothing else bring it to birmingham and we can do it in a couple of hours ..including the program.

corvette1989bham

For the most part, you cant just take the OLD ccm and upload it to the new

ccm it HAS to be in the car (please dont correct me about the off board programming module - I know it exists but few if any dealers have it, and when they do -they dont know how to use it)

USAFPILOT

So the new CCM has to be in the car to program it? The dealer says they will program it for me once I get it replaced and running I guess. I read in the manual you have to have it done before you drive a hundred miles or the mileage info wont download from the old into the new. Then you have to have a odometer correction plaque affixed to your door jam. I dont really want that. Though it would be cool to see low miles on the odo

Jeffvette

When you replace the CCM it will need to be programmed for VATS and mileage. The mileage can be changed within 100 miles of driving before it is perm locked. So if you plan on changing the ccm at home, you will not be able to drive it to the dealership.

Changing it is a excercise in patience. It's not pretty. But yes you will need a tech 1 to program it. I'm fairly certain a tech 2 will not handle it

Trizney

The older CCMS GM can not get. I have gone through this with a 1990
L98. I was able to find a company by searching through Google that said they had them. They rebuilt them and set them to a factory default ready to be coded. We never ordered one, as the problem ended up being the ECM. It was a really weird issue.

And if the CCM is bad, there is no way to pull the information off it to code the new one. And Jeff is right, the Tech 2 will not program it. I was told a Tech 1A was needed to program it.

To get to the CCM, you need to remove the driver seat, the interior pieces by the legs, the underdash on the driver side, and if you remove the radio, it makes it easier to snake out.

Like Jeff said, you need patience, but it is not hard.

Also, why did M say it was the CCM?

What problems are you experiencing?

-=Jeff=-

nope that is exactly right..

almost every dealer NEEDS the old one int he car to verify mileage before programming the new one as well ( another way to keep the ODO correct)

corvette1989bham

And BTW not only do you need a Tech1 you MUST have the Tech1 OBD interface (94 and 95 only) if you dont believe just try it. AND you only get one shot and getting it programmed, mess something up, hit the wrong key, pull the power cord out, Time to redo and start with another NEW ccm.

So you havent answered WHY you need a new CCM...what is the problem?

902066

Changing the ccm yourself is not a mistake, it takes time and patience. When I needed one I contacted Gorden Killebrew, he told me I could get a rebuilt one from K&B Special Products 5175 Overbend Trail Suwanee Ga. 30174 [Ken Anderson 770 932 0867.] It has been about 4 years ago dont know if contact info. is any good now, if not I would contact Gorden, both men are very helpful. At the time the rebuilt ccm was only a little over a $100.00 I believe.

The dealer I bought my Z from [Buds Chevy] programed the mileage in for me. They didnt need the old ccm, took about 5 min. cost about $25.00, has worked great for 4 years, but I thought you had to have the new ccm programed within 50 miles of putting it in. My Z is a 90.

The worst part of the job is unplugging and replugging in the ccm. There is not a lot of extra cable, and space is tight. My oldest daughters small hands helped a lot. It can be done especially if you hate to have others work on your car. Jim

USAFPILOT

Well...I got the bad one out...

I needed a new one because the old one must have shorted when I tried to charge the battery or during a jump start attempt. If you read in the manuyal all the stuff it controls including the vats, the pke, the courtesy lights, the speedometer DIC, etc. It was all having fits while everything else was normal. Every now and then the car could still crank, but very very rare...maybe once out of 20 attempts.

The hard part was unplugging it, took a lot of patience and a a permanently bent neck, might have been easier with the seat out. The good news is only the left underside of the dash has to be removed and there is an acess panel that lets you get to it.

Once I get a new one, I plan to just plug it in and see if the car comes back to life before I button it up. I should be able to crank it up and check all the systems before I send it back to chevy dealer for programming correct?

Why wouldn't you be able to reprogram on e of these ccm more than once?

They will owe me a second if they screw up the first.

USAFPILOT

this ccm is old school...too bad I cant replace it with a pentium or something.

corvette1989bham

There is a built in security feature that prevents more than one programming attempt. The dealer should NOT BY LAW program the ccm that YOU installed. If you dont program it, the car will run but some of the smart functions wont work and and gm dealer can tell via tech 1 or tech 2 for this that the ccm has been changed and the mileage is incorrect. The person that said he had a dealer program it after he installed is a fluke and the dealer should be put out of business. this is how people get ripped off by mileage tampering. There are security feature built in that makes it possible to tell theccm has been replaced and correct mileage not installed. Once that is done, the car is branded for life and is worth salvage.

corvette1989bham

As I posted earlier, I would have been happy to help, and dont think in any way you are tampering with mileage but I will say this to JeffVette and others on this board with the required knowledge no more is needed to be added to this thread about ccm security features as anyone has access to this thread even if they dont have the tools, this isnt public information. No one should program a ccm for someone with out the car being in the shop and mileage being verified and the cars stays PARKED at the shop until the units are changed. If someone wanted me to program a ccm that I didnt install, first of all I wouldnt , but if it was for a friend or board member they would have to bring the car to my place with the old ccm in it, let me see the mileage and they could swap in my parking lot themselves THEN I would program it.

Jeffvette

USAFPILOT

I also agree...my problem is that the CCM wont even give out the mileage...the speedo doesn't read...i dont even know what it was. I know it turned over 46,000 but that is it. I told the dealer when I had it there that it was 46K and thats what they wrote on their form, but I have no idea whether or not this old CCM can give out the correct mileage, I guess I am going to gave to guess the best I can, maybe go with 46.5K just to be safe. I thiink I might trailer it up there and let them set it if it all works when I plug it in...the dealer is only about 10 miles from my house but I dont want to chance anything.

902066

Hey Jeffvette,
I never said the mileage wasnt verified. I think you have a habit of making assumptions. Mabe the dealer knows my mileage and car well having seen it the week before for an unrelated issue. I think you should be put out of bussiness. Jim

Jeffvette

Oh good lord. Might want to go back and read who was saying that.

902066

Good Lord,

Sorry Jeffvette, I feel just like Kevin Kurtz. Im going to bed. Jim