GM S10/S15/Sonoma Pick-Ups 1982-1993 Repair Manual

Transmission Converter Clutch (TCC) System


All vehicles equipped with an automatic transmission use the TCC system. The computer control module (ECM or PCM, as applicable) controls the converter by means of a solenoid mounted in the outdrive housing of the transmission. When the vehicle speed reaches a certain level, the computer module energizes the solenoid and allows the torque converter to mechanically couple the transmission to the engine. When the operating conditions (according to various sensors) indicate that the transmission should operate as a normal fluid coupled transmission, the module will de-energize the solenoid. Depressing the brake pedal will also return the transmission to normal automatic operation.