Traction Control General Description
TCS ACTIVATIONThe Traction Control System (TCS) also monitors rear wheel speed and compares the speed to the speed of the front wheel. If excessive rear wheel speed is detected in either rear wheels the TCS will be activated. The TCS uses the following to improved traction and vehicle stability:
- Fuel control
- Timing control
- Rear brake intervention
EFFECTS OF TCS
Traction control will not have any effect on the operation of the vehicle until the control module detects one or both of the front wheels rotating faster than the rear wheels. At this time the Electronic Brake and Traction Control Module (EBTCM) will request the Powertrain Control Module (PCM) to reduce the amount of torque applied to the drive wheels. The PCM does this by retarding timing and selectively turning off fuel injectors. The EBTCM will apply the rear brakes, thus reducing torque to the rear wheels. Once the rear wheels begin to rotate at the same speed as the front wheels, the system will return full control to the driver. During Traction Control mode, if the brake is applied to only one rear wheel, most of the torque from the engine will be directed to the other rear wheel which will improve the traction of the vehicle. 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. The TCS may be deactivated by the driver if desired. In order to deactivate the TCS with the engine running depress the Traction/Suspension Control switch. The system will remain deactivated until the ignition switch is cycled, or the switch is pressed again.
MAGNA STEER
The Speed Dependent Steering System or Magna Steer(r), incorporates its controller into the EBTCM. Magna Steer3 DTC C1241 will not cause any indicators to turn ON. Refer to DTC C1241 Magna steer Malfunction in Variable Effort Steering for DTC C1241 diagnostics.
VENT TUBE
Pin 16 of the EBTCM harness connector is a plastic vent tube that vents the cavity between the EBTCM and the BPMV to the passenger compartment.