Why does the ABS light come on when starting the car?

[McEmilio]

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.

[LeviFitz]

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.

[MacEvelyn]

I often help friends maintain old cars, and frequently encounter situations where the ABS light remains on after starting. This is usually a signal of system malfunction, with common sources being the sensor or circuit: the sensor gets damp and rusty, leading to inaccurate sensing; aging and broken wiring causes signal interruption; internal components of the module age and fail. A momentary alarm during startup might be a temporary phenomenon, such as voltage fluctuation, but if it stays on, it needs serious attention. Ignoring it can lead to reduced braking performance, longer braking distances on slippery roads, and increased risk of rear-end collisions. Handling it isn't difficult: first, manually clean the wheel sensor area to ensure there's no dirt; if the light remains on, find a reliable garage to scan for fault codes, and replacing a small part can solve the issue.

[DelCaden]

Since my early days driving trucks, I've seen the ABS light come on quite often. If the light doesn't go off after starting, it's usually due to a wheel speed sensor failure or wiring issues, such as the sensor being damaged by a rock or a short circuit. If it remains on continuously, it means the anti-lock braking function has failed, making it easy to lose control when braking, especially at high speeds on icy roads. When addressing this, first check if the area around the tires is clean, and replace the sensor unit if necessary.