Why Is My ABS Light On? Common Causes and What to Do
Your ABS light comes on when the anti-lock braking system has detected a malfunction. When the light is illuminated, the anti-lock braking feature may be disabled until the problem is fixed and the error code is cleared.
The ABS light does not mean your brakes have failed. Your regular brakes still work when the light is on. What you lose is the anti-lock function that prevents the wheels from locking up during hard stops, which means reduced steering control and increased stopping distance on wet or icy roads.
The ABS light should briefly illuminate every time you start the car as part of a system check. If it stays on, there is a problem.
Dirt and debris around the ABS sensor can sometimes trigger an ABS warning light, so cleaning the sensor should be one of the first checks. View the Full Guide
Common Causes of an ABS Light
Faulty Wheel Speed Sensor.A wheel speed sensor sits on the wheel hub or axle and is exposed to heat, water, and road debris. A dirty, corroded, or disconnected sensor sends erratic signals — or none at all — to the ABS control unit, triggering the warning light.
Low Brake Fluid.Low brake fluid levels reduce hydraulic pressure and trigger the ABS light. Since brake fluid does not simply disappear, low fluid usually indicates a leak that should be repaired by a professional.
Blown ABS Fuse.The ABS system runs through a fuse, so if that fuse blows due to a short circuit or a surge in current, the system shuts off and the warning light comes on.
Bad ABS Module.The ABS module processes sensor data and controls brake pressure, and when it fails from heat, moisture, corrosion, or vibration, the warning light stays on or braking response becomes inconsistent.
Damaged ABS Tone Ring.The tone ring spins with the wheel to provide readings to the speed sensor, and rust or cracks that chip it away disrupt those readings and trigger the warning light.
Hydraulic Pump Problem.The ABS hydraulic pump controls brake pressure when the ABS is activated, and when it fails due to brake fluid contamination, electrical failure, or wear, the system shuts off and the warning light comes on.
What to Do When the ABS Light Is On
An anti-lock brake malfunction is not likely to affect normal braking, but the ABS may not activate during hard stops or on slippery surfaces when you need it. This results in reduced steering control and increased stopping distance.
If the light stays on, have it checked. A technician can scan the vehicle for trouble codes and pinpoint the issue. Not all diagnostic scanners can read ABS codes, so a proper diagnosis requires equipment that can access the ABS system.
While the ABS light does not mean your vehicle cannot be driven, driving without ABS is less safe, especially on slippery roads. If you drive with the light on, use extra caution and avoid situations that call for emergency braking.
