Wanted: Tech 1A

[Joshie225]

My 1994 Corvette needs CCM reprogramming. Does anyone have a Tech 1A for sale or rent? EBay only has adapters at the moment.

Thanks,
Josh

[kur4o]

Tech2 might work just as good. It does have support from 91-on. It can flash 94 pcms but never heard of ccm flashing. Do you mean setting some options on the ccm. Do you have service manual explaining the reprogramming?

[Joshie225]

Here's the situation...

The CCM was recently replaced, but 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. The factory service manual states: "Refer to the Tech 1 or CAMS (T-100) User's Guide for detailed programming information for the CCM, PCM or ECM.

[1project2many]

Hello,

I have never tried reprogramming a CCM but the information here (https://www.corvetteforum.com/forums/c4-tech-performance/4135835-need-help-with-ccm-reprogramming.html) agrees with many posts on different threads. It appears the CCM, like many other modules today, can be programmed after initial installation but most of the CCM details are "locked" once programmed. If you read the thread there is a link to a vendor who will rebuild your CCM and will program it with relevant data. Rather than buy a tool which does not appear to have the ability to make the changes you want, you may want to talk with the vendor who claims to be able to do the job. Yes, removing the CCM will require some work.

[kur4o]

It is an options setup with the ccm. With tech2 you can setup most of the items. Here is a list.

[Joshie225]

I'd read that thread before. All I need to change is the engine type so that CCM code 81 goes away and takes the "SYS" message with it. There is nothing else wrong so the CCM does not need tobe removed or rebuilt.


Hello,

I have never tried reprogramming a CCM but the information here (https://www.corvetteforum.com/forums/c4-tech-performance/4135835-need-help-with-ccm-reprogramming.html) agrees with many posts on different threads. It appears the CCM, like many other modules today, can be programmed after initial installation but most of the CCM details are "locked" once programmed. If you read the thread there is a link to a vendor who will rebuild your CCM and will program it with relevant data. Rather than buy a tool which does not appear to have the ability to make the changes you want, you may want to talk with the vendor who claims to be able to do the job. Yes, removing the CCM will require some work.

[Joshie225]

This meets my expectations. I have an appointment tomorrow at the local Chevy dealer and they have a Tech 2. Hopefully they also have the correct adapter for the 16-pin OBD 1.


It is an options setup with the ccm. With tech2 you can setup most of the items. Here is a list.

[1project2many]

It is an options setup with the ccm. With tech2 you can setup most of the items. Here is a list.

I'm concerned it's like some of our Ford and Chrysler modules which allow initial configuration but do not allow changing once programmed.


I'd read that thread before. All I need to change is the engine type so that CCM code 81 goes away and takes the "SYS" message with it. There is nothing else wrong so the CCM does not need tobe removed or rebuilt.
If the configuration cannot be changed with a handheld scantool, what is the next step?


This meets my expectations. I have an appointment tomorrow at the local Chevy dealer and they have a Tech 2. Hopefully they also have the correct adapter for the 16-pin OBD 1.
Good luck.

[Joshie225]

The dealer couldn't help. They also didn't have a Tech 1 or Tech 2, but something newer. The tech couldn't find any changeable options in the CCM, but was able to read the VIN and it matches. I really wish I had a Tech1 or 2 so that I could dig around myself. All that the CCM edit will get me is rid of the SYS message and probably allow the CCM to display PCM DTCs. It's not a big deal as the car runs well and I can pull PCM codes with EEHack. I'm not going to invest much more time or energy on the CCM right now.