The main reasons for the failure of ABS speed sensors include physical pollution, line failure, electrical problems, aging of accessories, and environmental and driving factors. The following are specific explanations:
Physical pollution or blockage: The sensing part of the ABS speed sensor may be covered by pollutants such as dirt and mud, affecting its ability to sense vehicle speed signals, causing the ABS computer to be unable to accurately judge the vehicle speed and wheel slip rate, and thus unable to issue corresponding action instructions to adjust the brakes. In addition, if the half-shaft gear ring of the vehicle speed sensor is attached with iron filings or other magnetic materials, it will also affect data reading.
Line connection failure: A loose system line connection is a common cause of failure. The vibration of the vehicle during driving may cause the connection parts, such as the speed sensor wire plug, to loosen, affecting signal transmission and causing the ABS system to misjudge. The line may also have short circuit or open circuit problems. Whether it is external force damage or the quality problem of the line itself, it may prevent the current from passing normally, causing the sensor to fail. In addition, poor contact of the ABS relay can also cause system failure.
Electrical problems: Unstable battery voltage or blown fuses may cause ABS system failure. When the vehicle battery voltage is insufficient or the generator output is abnormal, the sensor cannot obtain a stable power supply; its normal operation will be affected, and the internal components may even be damaged due to voltage fluctuations.
Accessory quality issues: If an ABS sensor of poor quality is selected, its internal components may not be able to withstand normal working intensity and environmental tests and are easily damaged during use. As the vehicle ages, the sensor will gradually age, the performance of the internal electronic components will decline, and eventually the sensor will fail. In addition, the offset of the installation position may also cause failures. If the sensor is not installed in the correct position, or the position is offset due to vibration during driving, the wheel speed cannot be accurately detected.
Environmental and driving factors: Harsh driving environments, such as muddy and dusty roads, may cause the sensor to be covered by pollutants, resulting in the contact signal not being able to work properly. In some complex road conditions, the sensor may also be damaged by collision, wear, corrosion, etc. In addition, bad driving behaviors such as frequent emergency braking and high-speed driving will put greater pressure on the vehicle's braking system, affect the working life and performance of the ABS sensor, reduce its braking sensitivity, and increase the probability of failure.