1992 Corvette, running fine when all of a sudden stalled at a red light.
Started up again but ran very rough and "jerky". A/C would blow cold then warm at the same time. If I got to another red light would have to throw the car into neutral and rev the engine to not stall again.(Automatic). Drove it to the dealer who said the "brain" is bad because they cannot get any codes off the car. Apparantly the brain is not easy to find and this dealer has placed a U.S. search of dealers to find one. Any ideas?

 

There are three main ones to choose from.

The CCM - Central Control Module. This guides all computers.
The ECM - Engine Control Module. This is the engine controller.
The EBCM - Electronic Brake Control Module. This controls the ABS and ASR.

What worries me is that if the CCM dies, the engine will continue to run, because it is not dependant on the CCM to operate, only to start the car (via the VATS handshake).

Now, with the various failures (AC/engine) I wonder what all has failed... the CCM monitors, but does not control, the climate control. Same with the stereo. Did the stereo freak?

So, which "brain" failed?

Depending on which, you may be better off with a reman unit (again, depending on which) or used (especially if it is the CCM). Now, one thing, the CCM stores mileage. When new, they can be programmed within the first 100 miles of installation, but after that, they are stuck. The CCM really never fails, it is VERY rare. However, if you need one, you may want to go used, and find one with the same option group and similar mileage. I don't remember for sure if the CCM is specific to options, tho... I will have to check my parts fiche to confirm.

 

Thanks for responding.

I think from what you say the CCM is bad-so the dealer thinks.

I didn't mention but the transmission was replaced for a "new" rebuilt unit from the same dealer about 150-200 miles ago, but they say this has nothing to do with it. Also a new alternator was put in about 300 miles ago. (car has 66,000 miles on it.)
Personally, I think this dealer is not that great and have a feeling when they replace the "brain" they will find something else wrong.

It's great for them, replace parts at my expense, for them to learn as they go.

Oh well,

 

They will have to if that doesn't solve the problem. It sounds like that are starting to throw money at it. The problem is...it's YOUR money. You might save a bundle if you pick up a FSM and start doing your own trouble shooting. Working on these things can be fun, but at the least, you can make yourself a better informed consumer.

RACE ON!!!

 

I checked the FSM this morning, whilst troubleshooting my car for another problem.

The ECM DOES have a direct effect on the AC system.

I am not convinced the problem is with the CCM.

Do you have the car, or is it at the dealer?

 

You may be right about the ECM and not the CCM. It's just that I dumped a lot of money into the car recently and figured I'd get more than 200 miles out of it. When they called with the "news" I knew I was "taken", I mean taken back.

It is at the dealer at this time. As I mentioned they are trying to locate whichever module they are looking for. I did not know you could get an aftermarket one or even a used one. Do you know who would stock one?

 

Check Ecklers and NAPA.

 

I own a 92 vert and recently had the problem that involved the CCM. This was the sysmptom: At freeway speeds my dash guages went out (everything). Made it home and parked the car in my drive way and turned it off. Tried to start it and nothing worked (VAT....). I could turn the lights on but that was it. About an hour or two later I could start the car. Shut it off and back to drawing board . Okay took the car to the dealership and was told that the tech could bypass the VAT system and the car would start (short version). I was told the CCM needed to be replaced. Thus the nightmare; the dealer had no on hand resources which meant a nationwide search was done to search out a refurbished CCM. It took 2.5 months to get one in my hands. Now the CCM is located in the dashboard (not easy to get to), and the dealership will charge you any where from $700~$850 to remove the dashboard. I did it myself and installed the new CCM. Started right up every time (dash gauges operative). Drove it to the dealership and had the burn in the neccessary data onto the new CCM configuration. The ECM did not need to be replaced (I had to replace the ECM about 3 years prior to the CCM failure). The corvetteform has helped me to enough info as to the number of possibilities that may encompass your issue and from there I was able to at least follow the technician when analyzing/troubleshooting my corvette. I found out that there are relay switches for damn near every eletrical device inside your dashboard and troubleshooting your eletrical will take time if you do it your self. Make sure that the tech burns all the same configuration that you had on your original CCM (milage/courtasy light/radio extendd play w/engine off, etc.). It sounds like your ECM has issues, but that's just my stab at the problem!

 

I was reading my FSM earlier, as I mentioned above.

The CCM is simply the VATS and a traffic cop. It won't effect the way the car runs once it starts.

Considering the AC freaked, and the engine failures, I am sure it's the ECM that has taken a crap.

One last thing - the ECM has a chip in it that MUST be transferred from the old ECM to the new ECM. Without that swap, the computer will not be worth spit.

 

Wow , whata story. Is it common for these odules to go bad? I hear of your 2 stories, but I wonder what the % is overall. I'll hear what the dealer has to say on Monday.

Thanks again.

 

I would say for all the module failures, the CCM just doesn't die that often.

The least common is the EBCM... mainly, it's in a weather proof, and low temp box. The CCM is in the dash below the radio. The labour they are nailing you for is insane.

 

Spoke with the dealership today. It is the ECM that needs replacing and again I am on a wait list until up to the end of "July". We can get an aftermarket module but it will not come with a warranty and he reminded me that if it is used and something else goes related to the aftermarket device they will not be responsible.----Soooo, I guess I'm stuck waiting.
SOUNDS LIKE b.s. BECAUSE WHEN YOU ORDER THE MODULE FROM eCKLER'S THEY WANT A CORE EXCHANGE, SO REALLY, WHAT IS THE DIFFERNCE ?

 

If I were you, I'd get on ebay and try to find an ECM. I've seen them go for under $100.

There are those who believe you are better off with a salvage ECM. The "rebuilt" ECM's have been known to solve one problem however another "new" problem shows up.

I'd get your part number off the current ECM and start shopping. Use your old chip.

Let us know.

dlmeyers 90 coupe zf6 3speed shocks

 

That makes me leary of getting one online or aftermarket. As the dealer has said, I could do this, but if something else fails, as you mention, they will not cover it.

Really, though , what is the big difference between the OEM module and an aftermarket one. I found one on Zip corvette's website for $95.95, however there is a $150.00 core exchange fee, so in essence they are just rebuilding an original module.

I wonder if that's all GM would do anyway, since the dealer cannot locate one in GM's inventory?

 

oh, God... they are being jerks.

If the ECM is faulty, I don't see how it can hurt any thing else.

Someone, if an ECM fails, what can it hurt?

 

Well, out of the blue the dealer called me to say the car was ready-"what?-you told me yesterday the part would take a while to come in"
Well, it came in later that day and they installed it.

Picked it up and it seems to ride fine-(only 35miles so far).

I'll let everyone know what happens/

Thanks