ANTI-LOCK BRAKE SYSTEM (ABS)

There is the following distinctive characteristics in the ABS vehicles compared with the non-ABS vehicles. Note that it does not indicate malfunction. - When the brakes are applied rapidly or on a slippery road surface, the ABS will activate; the brake pedal will pulsate slightly and the vehicle and the steering wheel will vibrate slightly.

1. It may happen that vibration is felt in the steering wheel, body, and/or brake pedal when the ABS is functioning; such vibration is simply an indication that the system is functioning. 2. The ABS warning light may illuminate under any of the following conditions: - When the vehicle is traveling on snow or ice with the parking brake activated or a brake dragging at one wheel. - When different size tires are used. - When tires of different gripping performance are used. - When (while the vehicle is jacked up or stuck) the front wheels only are spun for 20 seconds or more. - When there is insufficient battery positive voltage.

The ABS is composed of electrical components, mechanical components (ABS hydraulic unit), and the components of the standard brake system. Fundamentally, malfunction of the ABS electrical or mechanical components is judged by the on-board diagnosis function within the ABS control module, and malfunctions are indicated by the warning light in the instrument panel. The location of a malfunction is indicated by the technician switching the system to the diagnosis-indication mode. The on-board diagnosis and indication functions must be used when diagnosing malfunctions of the ABS.