Anti-Lock Brake System: Operation
In anti-lock braking mode (wheel speed signals indicate a wheel is about to lock-up), ABS ECM operates 4 independent control solenoids to increase or decrease pressure as necessary to prevent wheel lock-up. This function continues as long as necessary during braking.
The ABS system also has a "failure" mode. When system detects a malfunction, the ABS ECM disables anti-lock braking and allows normal braking only. System then stores Diagnostic Trouble Code (DTC) and illuminates ABS warning light (ABS service reminder indicator). Trouble codes are retrieved for diagnosis through ABS warning light. See RETRIEVING & CLEARING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM.