Electronic Brake Control Module: Description and Operation

DESCRIPTION
The controlling element of ABS VI is a microprocessor based Electronic Brake Control Module (EBCM). Inputs to the system include four wheel speed sensors, the brake switch, ignition switch, and unswitched battery voltage. Outputs include three bi-directional motor controls, four indicator controls, two solenoid controls, and the system enable relay. A serial data line, located in terminal 9 of the Data Link Connector (DLC), is provided for service diagnostic tools and assembly plant testing.

OPERATION
The EBCM monitors the speed of each wheel. If any wheel begins to approach lock-up and the brake switch is on, 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. Additionally, the EBCM monitors itself, each input (except the serial data line) and each output for proper operation. If any system malfunction is detected, the EBCM will store a DTC in nonvolatile memory (DTCs will not disappear if the battery is disconnected). There is no serviceable or removable PROM. The EBCM must be replaced as an assembly.