ABS Description and Operation: Notes

This vehicle is equipped with the MGH 60 Mando electronic stability control antilock brake system. 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.

The following vehicle performance enhancement systems are provided.

• ABS
• Electronic brake distribution
• Hill Start Hold
• Traction Control System
• Vehicle Stability Enhancement System

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.
• Brake pressure modulator-The brake pressure modulator contains the hydraulic valves and pump motor that are controlled electrically by the electronic brake control module. The brake pressure modulator uses a four circuit configuration with a diagonal split. The brake pressure modulator directs fluid from the reservoir of the master cylinder to the left front and right rear wheels and fluid from the other reservoir to the right front and left rear wheels. The diagonal circuits are hydraulically isolated so that a leak or malfunction in one circuit will allow continued braking ability on the other.

  The brake pressure modulator contains the following components:

  • Pump motor
  • Inlet valves (one per wheel)
  • Outlet valves (one per wheel)
  • Two traction control/stability control supply valves
  • Two traction control/stability control isolation valves
  • Brake pressure sensor
• Wheel speed sensors - The wheel speed sensors are Active sensors that receive a 12-volt power supply voltage from the electronic brake control module and provides an output signal to the module. As the wheel spins, the wheel speed sensor sends the electronic brake control module a DC square wave signal. The electronic brake control module uses the frequency of the square wave signal to calculate the wheel speed.
• Traction Control Switch - The vehicle stability enhancement system and the engine torque reduction function of the traction control system are manually disabled or enabled by pressing the taction traction control switch.
• Steering Wheel Angle Sensor - The electronic brake control module receives serial data message inputs from the steering wheel angle sensor. The steering wheel angle signal is used to calculate the driver intended driving direction.
• Multi-axis Acceleration Sensor - The yaw rate and lateral acceleration sensors are combined into one multi-axis acceleration sensor, external to the electronic brake control module. The electronic brake control module receives serial data message inputs from the yaw rate and lateral acceleration sensor and activates stability control depending on multi-axis acceleration sensor input.