Anti-Lock Brake System With Traction Control System - BOSCH 5.3: Description

CAUTION: See ANTI-LOCK BRAKE SAFETY PRECAUTIONS article in GENERAL INFORMATION before servicing anti-lock brake system.

The Bosch 5.3 Anti-Lock Brake System/Traction Control System (ABS/TCS) increases vehicle steerability, directional stability and optimum deceleration in severe braking conditions on most road surfaces. The ABS monitors wheel speed and controls brakeline pressure to eliminate uncontrolled skidding.

The system also monitors rear wheel speed and compares it to front wheel speed. If excessive front wheel speed is detected at either front wheel, TCS will be activated. TCS uses engine fuel/timing management to provide improved traction and vehicle stability. The TCS uses front brake intervention to assist the wheel slip condition.

Major system components include Electronic Brake Control Module (EBCM), wheel speed sensors, instrument cluster warning indicators, brakelight switch, TRAC on/off switch, solenoid valve relay and pump motor relay, Dynamic Rear Proportioning (DRP), and Brake Pressure Modulator Valve (BPMV) assembly. BPMV assembly houses electric pump motor and solenoid valves. EBCM and BPMV assembly is located on left rear of engine compartment.

The dynamic rear proportioning (DRP) is a control system that replaces the hydraulic proportioning function of the mechanical proportioning valve in the base brake system. The DRP control system is part of the operation software in the EBCM. The DRP uses active control with existing ABS in order to regulate the vehicle's rear brake pressure. The red brake warning indicator is illuminated when the dynamic rear proportioning function is disabled.

NOTE: For more information on brake system, see appropriate DISC & DRUM article.