Why does the ABS light come on after vehicle inspection?
2 Answers
After the vehicle inspection, the ABS light comes on because during the tailpipe emissions test, only the two front wheels of the car are rotating while the rear wheels remain stationary. This causes the ABS to mistakenly believe there is a system issue, thus illuminating the warning light to prompt the driver to check the system. During the annual vehicle inspection, the first test item is the tailpipe emissions test. Each wheel is equipped with an ABS sensor that continuously monitors the wheel speed. Under normal driving conditions, the rotation speeds of the front and rear wheels cannot differ significantly. Since during the inspection process, the car's front wheels rotate for an extended period while the rear wheels remain stationary, the ABS may misinterpret this as a system malfunction, triggering the warning light to alert the driver. This does not indicate an actual ABS failure. If the ABS light comes on, simply turning off the engine and waiting for a dozen seconds before restarting will usually cause the ABS light to turn off by itself. If it doesn't turn off immediately, driving for a short period will also cause it to extinguish. This is not a sign of vehicle damage during the inspection. The ABS (Anti-lock Braking System) is designed to automatically control the braking force during vehicle braking, preventing the wheels from locking up and maintaining a rolling-sliding state. This ensures optimal traction between the wheels and the road surface, enhancing the safety factor of emergency braking while driving.
I've encountered the ABS light coming on after vehicle inspection several times. Based on my over 20 years of driving experience, it's most likely that the ABS sensor or wiring was accidentally disturbed during the inspection process. During annual inspections, technicians often test the brake system. If the sensor connector isn't properly reconnected after being unplugged, or if the wheel speed sensor gets dirty during tire removal/installation, it can trigger the warning light. The ABS (Anti-lock Braking System) prevents wheel lock-up during emergency braking. If it malfunctions, wheels may lock and skid during hard braking, especially increasing accident risks in rainy or snowy conditions. I recommend pulling over immediately to check - try restarting the engine to see if the light goes off. If it remains lit, take the vehicle to a professional repair shop for diagnosis right away. Also remember to regularly clean sensor areas during routine maintenance to prevent dust buildup causing issues.
