Happy new year everyone! I need some brain help here.
I've owned my '95 Chevy Caprice 9C1 (police package) for 10+ years and 50k miles and it has NEVER locked the TCC on its own since the day I bought it. I've had three different transmissions in it, two different torque converters, three different PCMs, multiple tunes, and nothing. Trans has a TransGo HD2 shift kit in it which overrode the TCC PWM solenoid, so it's just on/off based on the TCC enable solenoid like a '94 B-car is setup (although the apply/release tables are still setup like a '95). I eventually wired in a switch that grounds the TCC solenoid and I've just manually locked it once I get up to cruise speed. The transmission will lock the converter no problem, every time I throw the switch. The transmission is a '95 with the correct harness and solenoids in place and hooked up. There were no DTCs present during the attached log.
According to the GM B-car Factory Service Manual (FSM), page 7A-8, the following components play a role in TCC operation:
- Cruise Control Release Switch (this car never had cruise control but I added it later, no change in TCC behavior).
- PCM
- TPS
- MAP sensor
- VSS
- ECT
Through Datamaster I have verified that all of these sensors and switches are working properly. I'm posting the tune and log I took this morning after a battery-disconnected PCM reset with the TCC override switch deactivated.
I took a look at the tables in the tune and the only thing I can think of now is that unless I've missed an ECM switch or constant, maybe the PCM is somehow running in Performance mode, which never locks the converter?
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