Why does the ABS light come on when starting the car?
2 Answers
Reasons for the ABS light coming on when starting the car: 1. ABS wheel speed sensor issue. The wheel speed sensor is located on the wheel and is easily contaminated by dirt or mud. A sensor covered with excessive dirt can affect the transmission of speed signals, causing the ABS computer to fail to determine the speed signal and trigger an alert; 2. Wiring connection failure, possibly due to a loose connection in the wheel speed sensor plug; 3. ABS control unit programming issue, most likely caused by mismatched or incorrect data within the control unit, requiring data readjustment; 4. ABS master cylinder issue; 5. ABS control unit circuit board failure, necessitating replacement of the computer. However, this type of failure is very rare. In some vehicles, the circuit board of the ABS control unit can even undergo simple repairs, such as reattaching detached solder joints.
As an owner who has driven several cars, I once had the ABS light come on during startup. After quickly checking the information, I realized it was the warning light for the anti-lock braking system. Generally, it's normal for the light to stay on for a few seconds during startup as part of the self-check process. However, if it remains lit after startup, it indicates a system issue. Possible causes include dirty or mud-clogged wheel speed sensors, or loose or short-circuited wiring. The sensors are located near the wheels and are prone to dust accumulation. Sometimes, unstable battery voltage during startup can trigger false alarms. In severe cases, it might be due to a faulty control module or a blown fuse. If not repaired promptly, the anti-lock braking function may be lost during braking, causing the wheels to lock up during sudden stops and increasing the risk of skidding in rainy or snowy conditions. I recommend not taking it lightly and visiting a professional repair shop early for a diagnostic check. Also, pay attention to wheel cleanliness during car washes to prevent issues from accumulating.
