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 EBTCM, which then translates this information into a rotation or wheel speed signal. The EBTCM is located on left front side of engine compartment.

When EBTCM determines wheels are about to lock-up, it activates BPMV assembly to increase or decrease hydraulic pressure to each wheel. The BPMV can supply only as much fluid pressure as applied by driver through master cylinder. The modulator valve alone cannot apply the brakes. A slight pulsation should be felt through brake pedal during modulator activation.

BRAKE, ANTI-LOCK, TRACTION ENGAGED and TRACTION CONTROL warning indicator lights should come on when ignition switch is turned to ON position and vehicle is started. If BRAKE, ANTI-LOCK, or TRACTION CONTROL warning light stays on longer than approximately 5 seconds after vehicle is started, system malfunction is indicated. See DIAGNOSIS & TESTING. TRACTION ENGAGED warning light will turn on when traction control system is active.

There are situations when it may be necessary to deactivate ABS with TCS. For example, if vehicle is stuck in snow. To deactivate system, depress TRACTION CONTROL DISABLE button for 2 seconds (with engine running). Button is located inside of glove compartment. TRACTION CONTROL warning indicator should turn on. System will remain deactivated until ignition switch is cycled.