The controlling element of the ABS system is a microprocessor-based Electronic Brake Control Module (EBCM). If the vehicle is equipped with traction control, the microprocessor is called the Electronic Brake Traction Control Module (EBTCM). 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 scan tools.
The EBCM/EBTCM monitors the speed of each wheel. If any wheel begins to approach lock-up and the brake switch is on, the EBCM/EBTCM 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/EBTCM monitors itself, each input (except the serial data line) and each output for proper operation. If any system malfunction is detected, the EBCM/EBTCM will store a DTC in nonvolatile memory (DTCs will not disappear if the battery is disconnected).
Removal & Installation
- Locate the EBCM/EBTCM under the instrument panel, to the left of the steering column.
- Release the EBCM/EBTCM from its bracket using the pressure tabs.
- Detach the electrical harness and remove the EBCM/EBTCM from the vehicle.
Installation is the reverse of the removal process. Verify that all electrical connections are secure.