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6
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Wheel speed sensor - front
7
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Brake pedal switch
8
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Anti-lock brake system (ABS)/Dynamic stability control hydraulic control modulator (HCU)
The ABS modulates brake pressure on each wheel independently to maintain vehicle stability during braking. The ABS continually monitors the rotational velocity of each wheel during driving 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/dynamic stability control 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 through the ABS warning 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 system includes the: •
anti-lock brake system •
lateral/yaw control •
full speed traction control. The dynamic stability control system manages the braking system to enhance the driver control of the vehicle.
The dynamic stability control system continually monitors the steering wheel angle, master cylinder brake pressure, front and rear wheel speeds and vehicle lateral/yaw rate acceleration.
The dynamic stability control module supports speed control and stability assist functions.
The lateral/yaw rate sensor supplies a signal to the dynamic stability control 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 by the steering wheel rotation sensor and the |