Anti-Lock Control - Stability Assist - VIN Range: G00442->G45703
Anti-Lock Control - Stability Assist - VIN Range: G00442->G45703
The anti-lock brake system (ABS) modulates brake pressure on each wheel independently to maintain vehicle stability during braking. The ABS continually monitors the rotational velocity of each wheel anytime the ignition switch is in the run position and determines if a tire is skidding when the brakes are applied. Only then does the ABS intervene to modulate the brake pressure to the skidding wheel. The modulation continues until the wheel rotates freely. The brake pressure is then restored and the modulate/restore cycle is repeated whenever skidding is detected. This cycle occurs at a rate of several times per second.
The ABS module is capable of detecting the following system conditions:
^ hydraulic valve failure
^ wheel speed sensor failure
^ ABS power relay short circuit
^ interconnect failures to the ABS sensors, power and ground to the ABS module
^ over/under voltage conditions
The ABS provides self-diagnostics and displays failure messages via the ABS indicator in the instrument cluster. Failure of the ABS module, for whatever reason, will not compromise the normal operation of the brake system.
The Dynamic Stability Control (DSC) system includes the:
^ anti-lock brake system.
^ yaw/lateral control.
^ full speed traction control.
The DSC system manages the braking system to enhance the driver control of the vehicle.
The DSC system continually monitors the steering wheel angle, master cylinder brake pressure, front and rear wheel speeds, vehicle yaw and lateral rate acceleration.
The yaw/lateral rate sensor supplies a signal to the DSC module, via a serial link, which monitors the vehicles rate of acceleration from its central axis in a sideways direction, and also the vehicles angular rotation around it's central axis.
The driver input parameters are continually monitored via the brake master cylinder dynamic stability control sensor, the brake pedal travel sensor and the steering wheel angle sensor.
DSC is enabled/disabled via the traction control ON/OFF switch.
Self-diagnosis of the DSC system is provided via the instrument cluster message center.
Traction control is an additional function added to the ABS/DSC system. The vehicles driven wheels are continually monitored for wheel spin relative to the calculated reference speed and to each other. If wheel spin is detected, the traction control function intervenes independently of the driver, applying brake pressure to the slipping wheel and reducing the engine drive torque supply. Meanwhile, brake pressure is modulated by the traction control until traction is re-established. Traction control brake actuation is diminished above 40 km/h (25 mph). Above this speed traction control relies primarily on engine torque reduction.
Traction control is enabled/disabled via the traction control ON/OFF switch. When the switch is in the (OFF) position, the amber traction control warning lamp solidly illuminates within the instrument cluster message center. The traction control is automatically activated when the ignition is switched on. Self-diagnosis of the traction control system is also provided via the instrument cluster message center.
The traction control brake intervention is automatically disabled whenever the brakes exceed a temperature limit. The traction brake intervention will remain disabled until the brakes have cooled, irrespective of ignition switch position or ignition switch cycling.
Anti-Lock Control - Stability Assist - VIN Range: G00442->G45703
Principle of operation
The anti-lock control - stability assist system includes the:
^ anti-lock brake system (ABS)
^ yaw/acceleration control
^ emergency brake assist
^ traction control
Anti-lock Brake System (ABS)
The anti-lock brake system (ABS) modulates brake pressure on each wheel independently to maintain vehicle stability during braking. The ABS continually monitors the rotational velocity of each wheel anytime the ignition switch is in the run position and determines if a tire is skidding when the brakes are applied. Only then does the ABS intervene to modulate the brake pressure to the skidding wheel. The modulation continues until the wheel rotates freely. The brake pressure is then restored and the modulate/restore cycle is repeated whenever skidding is detected. This cycle occurs at a rate of several times per second.
The ABS module is capable of detecting the following system conditions:
^ hydraulic valve failure
^ wheel speed sensor failure
^ ABS power relay short circuit
^ interconnect failures to the ABS sensors, power and ground to the ABS module
^ over/under voltage conditions
The ABS provides self-diagnostics and displays failure messages via the ABS indicator in the instrument cluster. Failure of the ABS module, for whatever reason, will not compromise the normal operation of the brake system.
Traction Control
Traction control is an additional function added to the anti-lock control - stability assist system. The vehicles driven wheels are continually monitored for wheel spin relative to the calculated reference speed and to each other. If wheel spin is detected, the traction control function intervenes, applying brake pressure to the slipping wheel and reducing the engine drive torque supply. Meanwhile, brake pressure is modulated by the traction control until traction is re-established. Traction control brake actuation is diminished above 40 km/h (25 mph). Above this speed traction control relies primarily on engine torque reduction.
The traction control brake intervention is automatically disabled whenever the brakes exceed a temperature limit. The traction control brake intervention will remain disabled until the brakes have cooled, irrespective of ignition switch position or ignition switch cycling.
Stability Assist
Dynamic stability control (DSC) maximizes vehicle stability under all conditions. The DSC system compares actual vehicle course to that intended by the driver. If the intended course differs from the actual course due to over steer or under steer conditions, the DSC system will brake individual wheels and reduce engine torque to bring the vehicle back to the driver's intended direction. By using a combined yaw rate sensor and lateral accelerometer, the vehicles rotational motion around its vertical axis and centrifugal forces generated while cornering are calculated to determine the vehicle's actual behavior. Using additional sensors for detecting steering wheel position and road wheel speed enables the system to recognize the driver's intentions.
Dynamic stability control is enabled/disabled via the DSC ON/OFF switch. When the switch is in the OFF position, the amber DSC warning lamp solidly illuminates within the instrument cluster message center. The DSC is automatically activated when the ignition is switched on. The DSC also provides failure messages via the instrument cluster message center.
Emergency Brake Assist
The emergency brake assist function allows the driver to enter ABS with greater speed and efficiency so that maximum braking is achieved sooner. Using the information received from the wheel speed sensors, brake pedal travel switch, master cylinder pressure transducer, master cylinder active booster solenoid and the yaw rate sensor and accelerometer, the ABS module detects whether more braking pressure can be applied in relation to how much braking pressure the driver is applying in an emergency braking situation.