GM Service Manual Online
For 1990-2009 cars only

This vehicle is equipped with the Bosch 2SH Antilock Brake System (ABS) and Traction Control System (TCS). The Bosch 2SH employs a single valve per channel, 3-channel system to reduce the tendency of any wheel to lock-up. This improves driver control of the vehicle during braking. The purpose of the ABS with TCS is to minimize wheel lockup during heavy braking on most road surfaces. The ABS performs this function by monitoring the speed of each wheel and the ABS performs this function by controlling the brake fluid pressure to each front wheel independently and controlling the brake fluid pressure to both rear wheels simultaneously during a braking maneuver. This allows the driver to retain directional stability and allows the driver better steering capability. This system also monitors the rear wheel speed for Traction Control. The rear wheel speed is compared to the speed of the front wheel. The TCS activates if excessive rear wheel speed is detected in either rear wheel. The TCS uses engine torque reduction and prevents transmission down shifting to provide improved traction and vehicle stability.