Anti-Lock Brake System: Operation

During normal driving and braking operations, ABS acts like a conventional braking system. Each wheel sensor constantly sends an AC voltage signal to Electronic Brake Control Module (EBCM). This information is translated to wheel rotation speed. When the EBCM detects wheel lock-up is about to occur, it activates the appropriate solenoid to pulse on and off rapidly, regulating hydraulic pressure to each wheel. A slight pulsation should be felt through brake pedal, indicating ABS is working.

BRAKE warning indicator will come on when ignition switch is turned to START position and should go off when ignition switch is turned to ON position. ANTI-LOCK indicator comes on when ignition is turned on and goes out after approximately 2 seconds. If either indicator stays on more than 30 seconds after vehicle is started, system malfunction is indicated. See DIAGNOSIS & TESTING.

Red BRAKE warning indicator will activate if parking brake is applied or brake fluid is low. Amber ANTI-LOCK indicator is controlled by EBCM and comes on if problem is detected with ABS. When indicator is on, ABS is disabled and braking is accomplished by conventional brake system. If both warning indicators are on, check conventional brake system for hydraulic system failure.