Electronic Brake Control Module: Description and Operation

ECU Electrical Connectors:

The 4WAL Electronic Control Unit (ECU) has a microprocessor and circuits that:

^ Monitor the brake switch input that tells it whether or not to prepare for possible antilock braking control
^ Operate the integral control unit assembly during antilock braking based on comparing the four wheel speed sensor signals to its own program stored in memory
^ Detect 4WAL system-related problems and take diagnostic action


The ECU has four electrical connectors:

^ A 2-way, with B+ and ground wire terminals for power supply
^ An 8-way (terminals A through H) that connects it to the wheel speed sensors
^ A 10-way (terminals A through K) that connects it to the rest of the vehicle's electrical circuits
^ A 2-way, with B+ and ground wire terminals for the pump motor

The ECU will disable antilock control, complete the "Antilock" light circuit, and store trouble codes if it detects one of the following conditions with itself:

^ Random-Access Memory (RAM) error (Code 71)
^ Read-Only Memory (ROM) error (Code 72)
^ Internal circuit error (Code 73)
^ Internal circuit error causing excessive isolation time (Code 74)