Traction Control

Traction control is a function of the PCM and the Electronic Brake Control Module (EBCM) that reduces front wheel slip during acceleration by applying the front brakes and reducing engine power. Refer to Traction Control System found within ABS Description and Operation in Antilock Brake System for an explanation of the role of the EBCM in traction control. The PCM continuously sends out a signal that indicates the torque output of the powertrain. This signal is delivered through the serial data link, and is used by the EBCM to determine what action is required when the EBCM senses the front wheels slipping. The EBCM may apply the front brakes only or apply the front brakes and request reduced torque output from the powertrain. The then PCM reduces engine torque by adjusting the ignition timing.

The PCM responds by shutting off fuel to one or more cylinders. The PCM does not shut off any fuel injectors if any of the following conditions are present:
^ The engine coolant temperature is less than -40°C (-40°F) or more than 131°C (268°F).
^ The engine coolant level is low.
^ The engine speed is less than 600 RPM.

The disabled fuel injectors will be enabled one by one as the need for traction control.

Several DTCs disable traction control when set. The DTCs also trigger a TRACTION OFF light or message. The PCM traction control override also disables traction control and triggers the message. To diagnose a Traction Off light/message, diagnose any DTCs set first. Then inspect the traction control override and, if active, deactivate the override. If the TRACTION OFF light/message is still present, refer to Diagnostic Starting Point - Antilock Brake System in Antilock Brake System for further diagnosis.