Anti-Lock Brake System: Description

Anti-Lock Brake System (ABS) consists of hydraulic actuator, solenoids, pump motor, ABS Electronic Control Unit (ECU), relays, deceleration sensor (4WD) and wheel speed sensors. See Fig 1.

An ABS warning light is located on the instrument cluster. Warning light comes on for 3 seconds as a bulb test when ignition is turned on. A primary check is performed after each engine start and initial vehicle speed exceeds 6 MPH. An actuator noise is heard as vehicle is started or as speed exceeds 6 MPH. This is normal. Anti-lock systems remains active until vehicle speed drops below 3 MPH.

Fig 1: Locating ABS Components

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