Traction Control (TCS) NW9

WARNING: This page is about a different car, the 2007 Hummer H2. However, it is still accessible from the selected car via links, so may be relevant.

The primary function of the Traction Control System (TCS) is to optimize vehicle performance with varying vehicle load and changing road conditions by controlling wheel slip at the driven wheels during an acceleration maneuver. The wheel slip is controlled by actively applying braking force. This modulation is applied and occur under all throttle input conditions where the difference between wheel speed' and vehicle speed indicate a loss of longitudinal traction.

TCS operation for each mode of driveline operation include the following. When high range is selected for the transfer case, the system controls wheel slip in the order of stability and acceleration. When low range is selected for the transfer case, the system controls wheel slip in the order of acceleration and stability.

A traction mode switch (TC2) is included to improve traction system performance on loose surfaces. The mode switch will have a momentary action and resets when the switch is pressed again or the ignition is cycled. The switch will have two states, one state is Road, and the other state is Loose Surface. When the switch is in the Road mode, the traction system will preform at its maximum, and in the loose surface mode will be adjusted for road conditions.

The braking is accomplished by closing the TCS Master Cylinder Isolating Valve, this isolates the master cylinder from the rest of the system. The TCS Prime valve opens to allow the pump to get brake fluid to build pressure for braking. The drive wheel circuit solenoids are energized as needed to allow for pressure hold, pressure increase, or pressure decrease.