Anti-Lock Brake System Operation

During normal driving and braking operations, ABS acts like a conventional braking system. Each wheel sensors constantly sends an AC signal to EBCM. This information is translated to wheel rotation speed. When EBCM determines that wheel lock-up is about to occur, it activates electro-magnetic valves, located inside valve block to increase or decrease hydraulic pressure to each wheel. A slight pulsation should be felt through brake pedal.

Warning lights should come on when key is turned on and vehicle is started. If either light stays on after approximately 30 seconds after vehicle is started, system malfunction is indicated. See DIAGNOSIS & TESTING .

The "BRAKE" warning light is controlled by Body Computer Module (BCM). Light will come on, if parking brake is applied, low brake fluid or low accumulator pressure. Light will be on when key is turn on. Light should go out after engine is started. "ANTI-LOCK" warning light is controlled by EBCM. Light will come on if EBCM detects problem with system. When light is on, ABS is partially or totally disabled.

The Graphic Control Center (GCC) on, will inform driver with message about certain problems, "BRAKE FLUID IS LOW/USE ONLY DOT 3 FLUID/FROM A SEALED CONTAINER/SERVICE NOW" or "ANTI-LOCK BRAKES/LOW BRAKE SERVICE CHECK REQUIRED" will be displayed when BCM detects problem. If parking brake is not fully released, GCC will display "PARK BRAKE IS ON/RELEASE BEFORE DRIVING". Message will be displayed only when vehicle is shifted from Park or Neutral to Reverse or Drive. Chime will sound for 30 seconds unless "System Monitor" button is depressed.