I'm trying to read my '95 F-body PCM (in a '76 Vette w/ a '95 Vette LT1) and getting an "Incorrect Message Sent" error.

I've contacted TunerCat and they gave me some things to check, but all look OK, except I do NOT have some files they say I should have: CommLog0.tst - CommLog4.tst. Tunercat said to send them these files if I can't figure it out, but these files are nowhere to be found???

I also noticed that the PCM is not "ticking" as they usually do when reading from / writing to. This "ticking" is normal, isn't it?

The fans do kick on (as they should) and the program starts to read, then suddenly quits, the fans kick back on, then the error message appears. Battery is fully charged, laptop is plugged in (not running on battery), all cables are securely in place.

I know I can fatally damage the PCM if flashing it and something like this happens.

I don't believe TC answers questions on the weekend, so if anything comes to mind...

Thanks

 

First of all, which version are you using for TunerCat. Are you using version 2.0? If that is so then use the flash and read utility direct from the TunerCat software. Or are you using the flash utility that came with the software package. I would highly recommend that you use the built in flash and read functions from within the program. You can use the latest flash utility from TunerCat and that should have come with your software. If you do not have the latest version of TunerCat and you do have a licensed copy, then just go to the TunerCat website and download the latest version.

Also what ALDL connector do you have? If you have the OBD2 style D shaped connector there has to be 12v ignition voltage at pin 16 which if you are looking at the end of the connector it would be the bottom row last pin on the right side. Pin 4 has to be chassis ground it is on the top row fourth pin from the left. The pins are arranged from left to right top row is 1 thru 8, bottom row left to right 9 thru 16.

If you have a early OBD1 connector that is rectangular shaped there is no power there at the connector. The cable that you have must have an additional power connector to it, that utilizes a cigarette lighter plug for a power supply. It sounds to me like there cable is not powered up and that is why you can’t get a read from it.

Using the flash utility to do the read, you can initiate a diagnostic while the program tries to read the PCM but I can’t remember how to do it and I can’t find information in the help menu on that subject. That is the file that TC wants you to send him.

Let me know about the power situation and I can try to help you further.

 

What's the current status of your ECM. Is it fully functional? Because that is the sort of behavior you get after you hose the ECM with a failed download. I expect there are other possible reasons for the behavior as well.