Corvette CCM Reverse Engineering Anyone?

[spfautsch]

where did you ground the Reman pin to on the CCM? one of my CCMs when I tried to program said the HW pin was not ready (grounded) I will try another, but that particular one i don't have the PASSKey figured out.. been through all the Keys and it has not gotten detected. I am trying again and letting it wait longer between codes to try

Ground, 0 volts. The heatsinks were usually where I'd attach the alligator clip. It's not clear from your question, but if you aren't seeing the security pin turn off (c47) I don't think it's possible to unlock for programming.

Please bear with me as I refresh my memory on this - it's been almost a year since I've looked at one and I have the worst memory.

NomakeWan I also have an 8051 PCM I can look at for the resistor you mentioned. I vaguely recall documenting something about that a while ago, possibly in this thread. There's definitely an impedance difference on the ALDL between the two.

Also jeff, here's how the odometer is stored, using your ZR-1 dump as example.

The odometer triplet is showing $00 12 46 FF FF ...

00 denotes how many FF bytes (aka erased flash cells) to skip during the read from left to right (until a tailing FF is encountered).

That makes $1246 the gross odometer reading minus the lower 4 bits, so $12460 = 74592 (decimal)

On the units I had access to, the remainder of the odometer reading was stored at $b657, in units of 0.25 miles. I referred to this as the vss counter since 1000 pulses = 1/4 mile. Yours reads $1b there, so 27 * 0.25 = 6.75. So my guess would be the ccm you dumped first is showing 74598 or 749599 miles. But its possible this second storage location is different on earlier bins. Let me know if that's close or not.

Edit: Since I just moved it, I know where my test bench cables are at, and I just happen to have a ccm thanks to AngryCorvair that I don't know the passkey value to (maybe I do, but I'll pretend I don't). Probably won't have a chance to do that until late tomorrow evening.