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My 1994 Corvette needs CCM reprogramming to fix a code and turn of the "SYS" message. Does anyone have a Tech 1A/Tech 2 to loan or rent? EBay only has adapters at the moment.
Here's the details...
The CCM was replaced before I bought the car the end of March. The dash displays the "SYS" message indicating a current-DTC malfunction. In CCM Diagnostic Mode I get "err" when the CCM tries to communicate with the PCM/Module 4, yet all the PCM data such as oil temp, fuel economy, etc are all displayed correctly indicating that the PCM is passing data to the CCM. I can also communicate with the PCM with EEHack and have no PCM DTCs. The CCM DTC is 81, Invalid Vehicle Configuration Detection (Engine Types Do Not Match). I believe that all I need to do is correct the engine type setting in the CCM.
If anyone can shed more light on the subject I'm all ears. Otherwise I'd like to borrow or rent the tool to change the CCM settings.
I purchased a tech 2 from a website in China for $275.00 shipped. All cables and adapters included. Just did not have a case included. I have had it for four years and so far so good.
Search for tech 2 from China and you will find several options if you are interested in buying one.
Thanks for the reply. I did find the Chinese knockoffs and asked if they were suitable for changing CCM/BCM options and was told no. Have you edited CCM options with yours?
I take your point, the Tech 2 will also need the correct software/firmware. This screen shot of a Tech 2 menu shows the option that I want to change so the Tech 2 appears capable.
Thanks to the generosity of forum member ChumpVette and his Tech 2 I now know more about the condition of my car. Going in I knew my car had CCM work done recently and that I had CCM code 81 set. What I didn't know was that the car was repaired with a CCM from a ZR1 meaning the engine type is set to LT5 which is the reason for the code 81, engine type mismatch. What we could not do though is change the engine type setting with the Tech 2. As this is really only a nuisance I'm going to let it ride for now. ChumpVette did float the idea of swapping in an LT5 and with that matching ECM I should indeed not have a CCM DTC 81, but that's a bit like wanting to go into orbit just for a little more sun.
You also are displaying odometer information from that ZR-1 or we should say your car started recording/adding miles from the ZR-1 CCM when it was installed in the car. Did you note the VIN of the ZR-1 while you were in the CCM OR maybe it wouldn't read the VIN. The C4 CCM likely uses the VIN code to match. I've never tried to edit a VIN in a C4 CCM using a Tech1 with the correct cartridge. @ChunpVette might likely have a Tech1 & the correct cartridge.and you could try. I know mileage/odometer can't be edited and I assumed that VIN was similar. It would be an interesting effort.
Actually, the shop that "rebuilt" the PCM got the VIN and odometer correct. They just neglected to change the engine type.
VIN & miles are in the CCM - you said that's where your error is. Your error is CCM expects to see a PCM/ECM info that matches the VIN (I believe) that's in the CCM.
Yes, they got the VIN and odometer correct, but the engine type in the CCM is LT5.
VIN & ODOMETER is in CCM - The CCM with the LT5 VIN doesn't match the PCM tune/programming.That's your error. The shop didn't and can't edit CCM. How many miles does the car display on the IP? Run your correct VIN through CARFAX, or others, maybe even your DMV (You don't mention state) and see if it doesn't flag a potential 'ODO -ERROR'. Some DMV toss ODOMETER collection/validation @ 10 years.
Mt car's VIN and mileage were programmed into the replacement CCM. The replacement CCM engine type was left as LT5. I have CCM DTC 81 as a result. Why is this so hard for you to understand?
Hey Dave, at some point and time with a previous owner, the CCM was replaced. The VIN and the mileage were input correctly as I verified the VIN in the CCM was a match to the VIN tag. It is recognizing the error as there should be an LT5 in the Engine bay, but there is an LT1. My interpretation of the error, is that it is seeing this through the PCM/ECM. Everything looks spot on, other than it is saying "Engine Type: LT5"
I have a tech1 and the CCM cartridge. Didn't even think to check it out and see if it had any more interaction power. But all ears if you have any other tips.
Hey Dave, at some point and time with a previous owner, the CCM was replaced. The VIN and the mileage were input correctly as I verified the VIN in the CCM was a match to the VIN tag. It is recognizing the error as there should be an LT5 in the Engine bay, but there is an LT1. My interpretation of the error, is that it is seeing this through the PCM/ECM. Everything looks spot on, other than it is saying "Engine Type: LT5"
I have a tech1 and the CCM cartridge. Didn't even think to check it out and see if it had any more interaction power. But all ears if you have any other tips.
'94 1st year PCM/CCM combo I've no idea BUT if you have Tech1 or 1A with all of the required adapters it would be interesting to look at the CCM using it. A Tech1 and a 1A require a different adapter combo for the access. I've never had a need or interest to attempt an edit of CCM info. I just check VIN and miles and I know miles can't be edited so I move on. What seems ODD is that an LT5 using an ECM through end of production and stores/compares no RPO content info that a CCM from an LT5 car if properly rebuilt/programmed the PCM would see LT5.
Like I mentioned it might be interesting to check a few sources CARFAX, and others looking for an odometer error. Just because a CCM displays mileage it doesn't mean correctly entered.
Did the Tech2 display a part # for the CCM. Tech1 & 1A I don't believe ever did.
I'd think maybe an error created by a 'TUNER' than a CCM programming error. RPO OPTION content until OBD2 I didn't think existed.
There were only what 448 LT5 cars in '94?. CCM is 1 year only - odds of a LT5 CCM finding it's way through the rebuild/reprogramming cycle and still error?
***Consider this! The CCM maybe isn't from a ZR-1 but when programmed (It's thought to be) and '94 had PCM options maybe it ASKED RPO/engine and a poor choice by whoever was doing the programming!!
***Consider this! The CCM maybe isn't from a ZR-1 but when programmed (It's thought to be) and '94 had PCM options maybe it [B] ASKED[/B} RPO/engine and a poor choice by whoever was doing the programming!!
Also a possibility, yes.
I have the receipt from the shop that did the CCM change. They sub-contracted and received the CCM itself from another place. The CCM was programmed to the VIN and mileage given to the CCM supplier.
I have the receipt from the shop that did the CCM change. They sub-contracted and received the CCM itself from another place. The CCM was programmed to the VIN and mileage given to the CCM supplier.
Is the shop local that did the CCM programming? You know what created the error so maybe DRIVE ON!!! is appropriate.
I realize I'm 18 months late or whatever, but thought to drop an idea -
Since you're familiar with EEHack, have you tried changing your PCM VIN *only* to the VIN the CCM wants using Flashhack? I wonder if perhaps the rest of the tune in the PCM is still LT1, it'll run the car just fine while also keeping an "LT5" CCM happy and not throw up a meaningless DTC.
Or please let us know if you've resolved this somehow? I'm curious.
I realize I'm 18 months late or whatever, but thought to drop an idea -
Since you're familiar with EEHack, have you tried changing your PCM VIN *only* to the VIN the CCM wants using Flashhack? I wonder if perhaps the rest of the tune in the PCM is still LT1, it'll run the car just fine while also keeping an "LT5" CCM happy and not throw up a meaningless DTC.
Or please let us know if you've resolved this somehow? I'm curious.
Won't work. The VIN programmed into the CCM is the same VIN programmed into his PCM. They match. There's nothing wrong there.
The problem is the CCM is expecting an ECM from a ZR1, and instead it's talking to a PCM from an LT1. That cannot be corrected by any kind of reprogramming because the OP (or previous owner, whichever did the CCM swap) already put over 100 miles on the car (which locks out the CCM for reprogramming). The only solution is to either ignore the error, swap to a new CCM with the proper program installed, or swap to an LT5 engine.
Last edited by Nomake Wan; Feb 19, 2021 at 12:46 AM.
Need Tech 1A or Tech 2 for CCM programming
