What is the reason for the ABS light coming on after a vehicle annual inspection?
2 Answers
The reason for the ABS light coming on after a vehicle annual inspection is: During the braking test phase, the brake test bench drives either the front or rear wheels to rotate, and the operator applies the brakes inside to measure the braking force. The ABS computer only receives speed signals from either the front or rear wheels, causing the computer to detect a fault, which then triggers the ABS light to illuminate. The solution is to turn off the engine and restart it, or drive a few kilometers, after which the ABS light will turn off by itself. ABS stands for Anti-lock Braking System, and its function is to automatically control the braking force during vehicle braking, preventing the wheels from locking up and maintaining a state of rolling and sliding, ensuring maximum traction between the wheels and the ground. ABS only activates when the vehicle requires emergency braking, effectively reducing braking distance and preventing skidding during sudden braking.
I've been repairing cars for over a decade and have encountered many cases where the ABS light comes on after annual inspections. A common cause is that during brake testing at inspection stations, the equipment makes the wheels rotate differently than normal driving conditions. When the wheel speed sensors detect this mismatch, they may mistakenly identify it as a system fault, triggering the warning light. Sometimes inspectors disconnect the battery or cause minor wiring disturbances during operations, and if the fault codes aren't properly reset, this can also trigger the light. Actual faults may include dirty sensors, loose ABS wiring connections at the wheels, or issues with the ABS pump itself. I advise drivers not to panic when they see the light - first safely pull over and check for obvious dirt or damage around the wheels. If nothing's visible, promptly visit a professional repair shop for diagnostic computer scanning, as ABS involves braking safety. When the light is on, it means the anti-lock function may be disabled, creating significant risks during rainy conditions or emergency braking - never ignore this warning.
