ABS Description and Operation: Notes

This vehicle is equipped with a Continental Teves Mk60/Mk70 brake system. On vehicles without stability control, the electronic brake control module and the brake pressure modulator are serviced separately. The brake pressure modulator uses a four circuit configuration to control hydraulic pressure to each wheel independently.

Depending on options, the following vehicle performance enhancement systems are provided.

• ABS
• Traction control
• Stability control
• Dynamic rear proportioning
• Hill start assist
• Hydraulic brake assist

The following components are involved in the operation of the above systems:

• Electronic brake control module - The electronic brake control module controls the system functions and detects failures. It supplies voltage to the solenoid valves and pump motor.
• Brake pressure modulator - The brake pressure modulator contains the following components:
  • Hydraulic pump with pump motor
  • Four isolation vales
  • Four dump valves
  • Two traction control/stability control supply valves
  • Two traction control/stability control isolation valves
  • Pressure sensor
  • High pressure accumulator
  • Low pressure accumulator
• Body control module monitors the brake pedal position sensor signal when the brake pedal is applied and sends a high speed serial data message to the electronic brake control module indicating the brake pedal position.
• Brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The sensor provides an analog voltage signal that will increase as the brake pedal is applied. The electronic brake control module monitors the brake pressure sensor which is integral to the brake pressure modulator.
• Instrument cluster - The instrument cluster displays the vehicle speed based on the information from the engine control module. The engine control module sends the vehicle speed information via a high speed serial data to the body control module. The body control module then sends the vehicle speed information via a low speed serial data to the instrument cluster in order to display the vehicle speed, either in kilometers or miles, based on the vehicle requirements.
• Multi-axis acceleration sensor - The yaw rate, lateral acceleration and longitudinal acceleration sensors are combined into one multi-axis acceleration sensor, external to the electronic brake control module. The electronic brake control module receives chassis serial data message inputs from the yaw rate, lateral acceleration and longitudinal acceleration sensor and activates stability control and hill start assist function depending on multi-axis acceleration sensor input.
• Multifunction switch - The traction control switch is a multifunction momentary switch. The body control module monitors the signal circuit from the traction control switch and sends a high speed serial data message to the electronic brake control module indicating the switch position. The traction control and stability control are manually disabled or enabled by pressing the traction control switch.
• Steering wheel angle sensor - The electronic brake control module receives chassis serial data message inputs from the steering angle sensor. The steering angle sensor signal is used to calculate the desired yaw rate.
• Wheel speed sensors - The electronic brake control module supplies a 12 V reference voltage to each wheel speed sensor. As the wheel spins, the wheel speed sensor produces an alternating current square wave signal. The electronic brake control module uses the frequency of the square wave signal to calculate the wheel speed. The electronic brake control module sends the wheel speed information via high speed serial data to the engine control module.