ABS Sensor

What could be the possible cause of the ABS warning light coming on on the instrument panel?

1. Wheel speed sensor failure: The sensor may be obscured by dirt, debris, or internally damaged, resulting in an interrupted or abnormal wheel speed signal.
2. Electrical wiring problem: A loose or short-circuited ABS relay, fuse, or wiring can cause poor signal transmission, triggering the warning light.
3. ABS control unit (ECU) or pump failure: A malfunction in the pump, pressure regulating solenoid valve, or the ECU itself may cause the light to illuminate after the system self-checks.
4. Other factors: Incomplete parking brake application, insufficient brake fluid, or abnormal tire pressure can also cause the ABS warning light to illuminate.
Why doesn't an ABS sensor failure immediately cause the brakes to fail?
1. Conventional braking system still functions: Even if the ABS sensor fails, the standard hydraulic brake system still provides braking force, but loses its anti-lock function.
2. System self-protection mode: Upon detecting a sensor abnormality, the ABS control unit automatically switches to "fail-safe mode," maintaining basic braking function and disabling ABS pulse intervention. 3. Redundant Design: Most models are equipped with four wheel speed sensors. If a single sensor fails, the system can still use the remaining sensor information for limited anti-lock braking control.
4. Early Fault Warning: The ABS warning light illuminates immediately when a sensor anomaly occurs, alerting the owner to prompt prompt repairs to avoid complete failure during emergency braking.