The BA/BF/FG Pcm’s (ecu) all have provision for 3 connectors, however the ‘C’ connector is only utilized, and will have pins present only on some models (ie BA/BF Turbo, BA/BF LPG, BF 4 and 5 speed Auto, FG Turbo)
The ‘A’ connector goes to the engine harness and connects items such as the coils, injectors, sensors, throttle body etc
The ‘B’ connector interfaces the PCM with the vehicle, and provides power to the PCM, connects to the pedal, diagnostics connector etc.
The ‘C’ connector is used on some models to operate the automatic transmission, boost sensor, and boost control solenoid, depending on model
