Circuit/System Description

WARNING: This page is about a different car, the 2009 GMC Sierra, 2009 GMC Cab & Chassis Sierra, 2009 Chevrolet Silverado, and 2009 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The torque converter clutch (TCC) pressure control solenoid controls pressure which is proportional to the current. The transmission fluid pressure from the TCC pressure control solenoid is directed to another valve which regulates the transmission fluid flow and pressure through the torque converter clutch valve to control the rate of TCC apply and release.

The transmission control module (TCM) provides B+ to the TCC solenoid, pressure control solenoid 1 (PCS1), and the main modulation/line pressure control solenoid (MAIN MOD) through a separate solid state device called high side driver 1 (HSD1). The TCM uses a low side driver to control the current flow to the TCC pressure control solenoid. The TCM controls the current to the solenoid by changing the amount of time that the low side driver is on.