Torque Converter Clutch

WARNING: This page is about a different car, the 2003 Pontiac Vibe. However, it is still accessible from the selected car via links, so may be relevant.

The Powertrain Control Module (PCM) uses signals from the Vehicle Speed Sensor (VSS) to detect Torque Converter Clutch (TCC) lock-up status. The PCM then compares the actual data with the TCC lock-up schedule in the PCM memory to detect mechanical trouble of the TCC solenoid and valve body.

The TCC solenoid is used to engage the lock-up clutch. The PCM outputs system voltage to turn ON (energize) or remove voltage to turn OFF (de-energize) to control the hydraulic pressure to the lock-up valve within the transaxle. The TCC solenoid is always OFF in 1st and 2nd gears. The TCC is ON in 3rd and 4th gears when the PCM deems it appropriate.

If the brake light switch is closed, the PCM will not allow the TCC lock-up to occur. The PCM also uses the brake light switch input for fuel cut-off control.