Circuit Description

The traction control system uses the antilock brake system in conjunction with the PCM fuel and ignition controls to limit drive wheel slippage during acceleration. The PCM controlled portion of the traction control system reduces engine torque by any or all of the following methods:

• Retarding spark timing.
• Altering air/fuel ratio.
• Altering boost PWM (VIN 1).
• Shutting OFF up to three injectors.

To determine the amount of torque reduction required, the PCM monitors the TCS Desired Torque PWM signal from the Electronic Brake and Traction Control Module (EBTCM). The PCM also provides a TCS Delivered Torque PWM informing the Electronic Brake and Traction Control Module (EBTCM) how much torque is being produced by the engine. The Desired Torque display on the scan tool indicates the amount of engine torque requested by the EBTCM. With traction control not active, Desired Torque should vary between 99% and 100%. The Desired Torque display on the scan tool is not the PWM duty cycle.