Anti-Lock Brake System With Traction Control System

ABS EBTCM monitors speed of each wheel and controls brake fluid pressure to each wheel Independently during a braking event. This allows driver to retain directional stability and better steering capability. TCS system also monitors rear wheel speed and compares it to speed of front wheel. If excessive front wheel speed is detected in either front wheel, TCS will be activated. TCS uses fuel, timing, cylinder and supercharger control, and front brake intervention to provide improved traction and vehicle stability.

Under normal braking, ABS functions like a standard brake system. If wheel locking tendency is noted during a brake application, ABS will enter anti-lock mode. During anti-lock braking, hydraulic pressure in individual wheel circuits is modulated to prevent any wheel from locking. A separate hydraulic line and specific solenoid valves are provided for each wheel. ABS can decrease, hold or increase hydraulic pressure to each wheel brake. However, ABS cannot increase hydraulic pressure above amount which is transmitted by master cylinder during braking. During traction control mode, one or both front brake assemblies may be applied automatically.

During anti-lock braking, a series of rapid pulsations will be felt in brake pedal. These pulsations are caused by rapid changes in position of individual solenoid valves as they respond to their desired wheel position. This pulsation is present during anti-lock braking and will stop when normal braking is resumed or when vehicle comes to a stop. A ticking or popping noise may also be heard as solenoid valves rapidly cycle. During anti-lock braking on dry pavement, tires may make intermittent chirping noises as they approach lock-up. These noises and pedal pulsations should be considered normal during anti-lock operation.

Vehicles equipped with ABS may be stopped by applying normal force to brake pedal. Brake pedal operation during normal braking should be no different than normal vacuum-boost systems. Maintaining a constant force of pedal will provide shortest stopping distance while maintaining vehicle stability.

Traction control will not have any effect on operation of vehicle until control module detects one or both front wheels rotating faster than rear wheels. At this time Electronic Brake Traction Control Module (EBTCM) will retard timing, cut power to fuel injectors turn off supercharger (if equipped) and apply front brakes, thus reducing torque to front wheels. Once front wheels begin to rotate at same speed as rear wheels, system will return full control to driver. During traction control mode, if brake is applied to only one front wheel, most of engine torque will be directed to the other front wheel which will improve traction of vehicle.

TCS may be deactivated by driver if desired. In order to deactivate TCS, with engine running, depress traction control disable switch. This will cause TRACTION OFF light in instrument cluster to illuminate. System will remain deactivated until ignition switch is cycled, or until disable switch is pressed again.