TORQUE CONVERTER CLUTCH (TCC) OPERATION
The ECM controls a solenoid valve mounted in the THM 700-R4 transmission to allow the torque converter to directly connect the engine to the transmission. This reduces slippage and improves fuel economy. The ECM uses information concerning vehicle speed, coolant temperature, throttle position and gear position (some models) to determine when to apply the TCC.
When operating conditions indicate that the transmission should function normally, or when the brake pedal is applied, the TCC solenoid is de-energized. This allows the transmission to return to normal automatic operation.