Normal Operation

The ABS module sends wheel speed sensor information to the PCM along the high-speed controller area network (HS-CAN) bus. The PCM compares the front wheel speed sensor information to the rear wheel speed sensor information to determine if traction control is necessary. If traction control is necessary, the PCM limits engine torque by regulating fuel and spark to the cylinders, to control the wheel slip. At the same time, the PCM sends the instrument cluster a message over the HS-CAN bus to flash the traction control indicator. The traction control indicator informs the driver that a traction control event is taking place.

The traction control switch is grounded along circuit GD134 (BK/VT) and is connected to the instrument cluster along circuit CCA15 (YE/GY). When the traction control switch is pressed, circuit CCA15 (YE/GY) is momentarily grounded to circuit GD134 (BK/VT). The instrument cluster senses this ground and disables the traction control system, the cluster also sends a message on the HS-CAN bus that the system is disabled. The system will remain disabled until the switch is pressed a second time or until the ignition switch is cycled.

• DTC C1093 Traction Control Disable Switch Circuit Failure - If the traction control switch closed for more than 2 minutes or if there is a short to ground on circuit CCA15 (YE/GY) during normal operation, DTC C1093 will be set. If the traction control switch closed during the instrument cluster self-test and for more than 2 minutes in during normal operation, DTC C1093 will be set.

This pinpoint test is intended to diagnose the following:

• PCM configuration
• Wiring, terminals or connectors
• Traction control switch
• HS-CAN bus
• PCM
• ABS module