According to the pinout at http://www.lt1swap.com/99-02_vortec_pcm.htm
Blue connector pins:
17 - trans fluid pressure switch b (presumably a binary input)
18 - trans fluid pressure switch c (ditto)
32 - PRND "A" input (not sure if digital or analog, likely digital)
24 - PRND "P" input (apparently binary, park/neutral)
79 - 2/3 shift solenoid control (what kind of control signal? binary, analog, PWM, etc?)
Red connector pins:
2 - TCC control solenoid (what kind of signal?)
6 - transmission fluid pressure control solenoid high (what kind of signal?)
8 - transmission fluid pressure control solenoid low
47 - transmission shift solenoid A (what kind of signal?)
48 - transmission shift solendoi B (what kind of signal?)
51 - transmission temperature signal - ?
The web page says this last pin is used only for AT, but I have a hunch my MT Corvette might use it for the transmission temp display in the instrument cluster.
If the solenoid outputs are PWM then one of them could presumably be re-purposed for boost control on forced-induction cars, with some hacking of the PCM firmware of course. Since the PCM knows throttle, RPM, and vehicle speed, one could presumably set up per-gear boost control tables.
An analog could potentially be re-purposed for use with an ethanol sensor for flex-fuel, again with some firmware hacking.
A digital input could be re-purposed as a valet switch to limit throttle on drive-by-wire cars to, say, 50%. Or limit RPM to 4000 on cable-throttle cars.
But since I've never paid much attention to how automatic transmissions work, I have no idea what sorts of signals these I/O pins were intended for. Does anyone know?
And while I realize that it's kind of early to start talking about this degree of firmware hacking for these PCMs, I'm pretty optimistic about the near future.
