Normal Operation

The traction control system operates using the ABS module to interact with the PCM to reduce engine torque if one or more of the drive wheels lose traction and begin to spin during acceleration. Engine torque modulation is achieved by regulating fuel and spark to the cylinders.

The stability control utilizes several sensor inputs (wheel speed, steering wheel rotation, stability sensor cluster, brake pedal) to monitor the vehicle motion relative to the intended course. If the system determines that a vehicle instability event is about to occur, it will take action to adjust brake torque at specific wheels and to reduce engine torque to reduce the cornering forces and, therefore, the total roll moment acting on the vehicle.

The stability/traction control switch is a momentary contact switch and is part of the liftgate release and hazard switch assembly. When the switch is pressed, ABS module circuit CCA15 (YE/GY) is momentarily grounded through the switch to circuit GD138 (BK/WH). The ABS module then sends information to the PCM along the High Speed Controller Area Network (HS-CAN) bus to modulate the engine torque.

This pinpoint test is intended to diagnose the following:

• Wiring, terminals or connectors
• Stability/traction control switch
• ABS module