Corvette CCM Reverse Engineering Anyone?

[spfautsch]

I think it's a little soon to say, but here's what I'm basing the two option bytes on, from the A297.DS file:

..PAGE
..HEAD02L CCM ALDL DATA LIST 
..HEAD03L NUMBER OF DATA WORDS - 23
..HEAD04L CCM ALDL MODE 1 DATA LIST (MESSAGE 1)
 BYTE  BIT  DESCRIPTION
 ----  ---  -----------
 1          FIRST PROM ID WORD (MSB)
 2          SECOND PROM ID WORD (LSB)
 3-19       VEHICLE IDENTIFICATION NUMBER

 20    0    REAL TIME DAMPING          0 = NO        1 = YES
       1    ANTI-LOCK BRAKES           0 = NO        1 = YES
       2    ELECTRONIC THROTTLE CONTROL              1 = YES
       3    RESERVE FUEL INDICATION    0 = NO        1 = YES
       4    OVERSPEED WARNING          0 = YES       1 = NO
       5    SPEEDOMETER BIASING        0 = YES       1 = NO
       6    ROUGH ROAD DETECTION       0 = NO        1 = YES
       7    NOT USED

 21    0    ENGINE                     0 = LT1       1 = LT5
       1    TRANSMISSION               0 = AUTO      1 = MANUAL
       2    MAGNETIC SPEED-DEPENDANT VARIABLE ASSIT  1 = PRESENT
       3    HVAC                       0 = C60       1 = C68
       4    LOW TIRE PRESSURE WARINING SYSTEM        1 = PRESENT
       5    SELECTIVE RIDE SYSTEM                    1 = PRESENT
       6    POWER SEAT, DIRVER SIDE                  1 = PRESENT
       7    POWER SEAT, PASSENGER SIDE               1 = PRESENT

 22    0    NOT USED
       1    NOT USED
       2    NOT USED
       3    NOT USED
       4-7  NOT USED

 23    0-7  NOT USED

Bytes 20 and 21 match $b6c6-$b6c8 pretty much exactly. The only "mainstream" head scratcher is the C68 option which seems like was standard equipment after 90 or 92. Everything else that was optionally available before 97 was incredibly rare save the FX3 (selective ride system). NomakeWan's 94 has this and the bit's cleared on the dump he posted. I have a message out to someone with a 92 ZR-1 with the FX3, but he would need hand-holding and his wife is in the hospital with cancer / chemo + covid so I think I'm going to leave him to be with his wife for the moment.

Everything else was either not available, or doesn't make any difference to the unit.

Real time damping wasn't an option until much later afaik.
ABS might have been a delete-able option but would have been a special order
ETC didn't come into the picture until the LS1 in 97
Bits 4-6 are all 1s in everything we have

In byte 21 the engine option was pretty obvious. I think this one is probably the most complained about fault code with a mis-configured ccm.
Transmission seems documented well enough
Electric power steering was also not available until 200?
C68 versus manual A/C controls is still a grey area, but I think not relevant to the function of the module since all our cars have it but none have this bit set
TPMS was a very rare option so may have some bearing on things - good luck finding someone with that option
FX3 seems to not have bearing on the ccm function
The power seat options are irrelevant because there are no inputs / outputs it could possibly effect

I'm still open to discussion on how to handle the reman pin location and whether to include (odometer) in the .xdf. An "experimental" version is attached.