Anti-Lock Brake System: Description
The rear anti-lock brake system monitors rear wheel rotation during braking and corrects brake pressure on rear wheels to prevent wheel lock-up. System consists of Anti-Lock Valve (ALV), brakelight switch, Electronic Control Module (ECM) and speed sensor. See Fig 1 . ANTI-LOCK indicator light operates in conjunction with BRAKE warning light to inform vehicle operator that system is operating correctly.
The ECM controls brake operation, based on input signals received from speed sensor and brakelight switch. A self-check is performed by ECM on anti-lock brake system every time ignition is turned on. See ABS FUNCTION TEST under DIAGNOSIS & TESTING. The ECM contains a self-diagnostic system used to diagnose anti-lock brake system if a failure occurs.