ABS Description and Operation: Notes

Callout	Component Name
1	Left Rear Brake
2	Master Cylinder Reservoir
3	Master Cylinder
4	Left Front Brake
5	Left Front Inlet Valve
6	Left Front Outlet Valve
7	Right Front Inlet Valve
8	Right Front Outlet Valve
9	Right Front Brake
10	Accumulator
11	Brake Pressure Modulator Valve (BPMV)
12	Return Pump
13	Pump
14	Priming Solenoid Valve
15	Accumulator
16	Return Pump
17	Right Rear Brake
18	Right Rear Outlet Valve
19	Right Rear Inlet Valve
20	Left Rear Outlet Valve
21	Left Rear Inlet Valve
22	Isolating Solenoid Valve

This vehicle is equipped with the Bosch 8.0 antilock braking system.

The vehicle is equipped with the following braking systems:

• Antilock Brake System (ABS)
• Traction Control System (TCS)

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

• Electronic Brake Control Module (EBCM)-The EBCM controls the system functions and detects failures.
• Brake Pressure Modulator Valve (BPMV)-The BPMV contains the hydraulic valves and pump motor that are controlled electrically by the EBCM. The vehicle uses a 4 circuit configuration with a front/rear split. The BPMV directs fluid from the reservoir of the master cylinder to the front wheels and fluid from the other reservoir to the rear wheels. The circuits are hydraulically isolated so that a leak or malfunction in one circuit will allow continued braking ability on the other.
  IMPORTANT: There is a rubber isolator located under the BPMV and on the mounting studs. The rubber isolators protect the BPMV and the EBCM from vehicle vibrations.

  The BPMV contains the following components:

  • Return pumps (2)
  • Pump motor
  • Accumulators (2)
  • Inlet valves (one per wheel)
  • Outlet valves (one per wheel)
  • Isolating solenoid valve
  • Rear priming valve
• Wheel Speed Sensors-As the wheel spins, the wheel speed sensor produces an AC signal. The EBCM uses this AC signal to calculate wheel speed. The front wheel speed sensors are replaceable only as part of the wheel hub and bearing assemblies.
• Traction Control Switch-The TCS is manually disabled or enabled using the traction control switch.
• Stop Lamp Switch-The EBCM uses the stop lamp switch as an indication that the brake pedal is applied.