Electronic Brake Control Module: Description and Operation

CONTROLLING THE ABS
The controlling element of ABS VI is a microprocessor based Electronic Brake Control Module (EBCM).

Inputs To The System - include three wheel speed sensors, the stoplamp switch, ignition switch, and unswitched battery voltage.

Outputs From The System - include three bidirectional motor controls, two solenoid controls, the ABS relay and the lamp driver relay. A serial data line is used for service diagnostic tools (scan tool) and assembly plant testing.

OPERATION
The EBCM monitors the speed of each wheel. If any wheel begins to approach lock-up, the EBCM controls the motors and solenoids to reduce brake pressure to the wheel approaching lock-up. Once the wheel regains traction, brake pressure is increased until the wheel again begins to approach lock-up. This cycle repeats until either the vehicle comes to a stop, the brake is released, or no wheels approach lock-up.

The EBCM Monitors Itself - each input and each output for proper operation. If any system malfunction is detected, the EBCM will store a Diagnostic Trouble Code (DTC) in nonvolatile memory. DTCs will not disappear if the battery is disconnected.

ELECTRICAL AND MECHANICAL INTERFACE
The wiring harness is the mechanism by which the EBCM is electrically connected to power and ground, wheel speed sensors, motors, solenoids, fuses, switches, lamps, ABS relay, lamp driver relay, and the serial data link. The components considered part of the wiring harness are the wires that provide electrical interconnection and connectors/terminals that provide an electrical/mechanical interface from the wire to a system component.