What is the reason for the ABS light coming on after vehicle inspection?
4 Answers
The reasons for the ABS light coming on after vehicle inspection are: 1. Air in the system pipeline; 2. Computer system malfunction; 3. Vehicle speed sensor failure; 4. ABS wiring harness breakage. If there is air in the ABS system pipeline, it will seriously interfere with the regulation of dynamic pressure, causing the ABS system to lose its function. If the computer malfunctions, the ABS will not work properly. The activation and deactivation of ABS are achieved by the vehicle speed sensor transmitting signals to the computer. If the vehicle speed sensor fails, the ABS will inevitably not work properly. Dirty sensor connectors or improper air gaps in the sensor can also cause poor sensor performance. For example, if the sensing part of the ABS vehicle speed sensor is covered by mud, sludge, or other contaminants, it will affect the sensor's ability to detect the corresponding vehicle speed signal.
During car repairs, I've encountered many cases where the ABS light comes on after annual inspections. The main reason is that the brake test during the inspection is too aggressive, causing the wheel speed sensors to vibrate or get covered in dust, leading the computer system to misjudge it as a fault. Another common cause is unstable battery voltage, which can cause issues with the ABS module during vehicle reset. In such cases, the illuminated light indicates that the anti-lock braking system is not functioning, making it very dangerous during rainy conditions or emergency braking as the wheels may lock up. I recommend first checking around the tires and wheels for any mud blocking the sensors. If restarting the car doesn't resolve the issue, promptly visit a professional repair shop to have the wiring harness inspected with diagnostic tools. Don't wait until an accident happens to address it.
Once after my annual vehicle inspection, the ABS light suddenly came on while driving home, which really freaked me out. I talked to an experienced driver who suspected that the testing equipment might have disturbed the sensor or the ABS connector was loose. It turned out that when I took it to the repair shop, they found the sensor terminal had been knocked askew—adjusting it fixed the light. This incident reminded me to clean the wheel hub area before inspections to avoid foreign objects interfering. If this happens, don’t drive fast—ABS failure can lead to loss of control during turns or hard braking. Safety first.
The ABS light indicates a fault in the anti-lock braking system. It may appear after an annual inspection due to sensor errors caused by hard braking during testing or voltage fluctuations that led to reset failure. This poses significant risks as it may result in reduced braking responsiveness in emergencies. Upon noticing it, I immediately slowed down and pulled over, then tried restarting the vehicle by turning off and on the ignition. If that doesn't work, seek professional repair immediately. Never ignore this warning light—it's crucial for driving safety.
