If your vehicle is showing abs warning light stays on, here are the most likely causes and the parts you'll need to fix each one.
Wheel speed sensors are mounted at each wheel and are constantly exposed to road debris, moisture, and brake dust. A buildup of metallic particles or an internal electrical failure will cause the sensor to stop reading, triggering the ABS light.
Very common after recent brake, strut, or suspension work. The delicate sensor wire can easily be pinched, stretched, or the mechanic may have simply forgotten to plug the connector back in.
The ABS sensor reads a toothed or magnetic 'tone ring' to determine wheel speed. If a wheel bearing has excessive play, it moves the ring out of alignment. Alternatively, the tone ring itself (often integrated into the bearing or CV axle) can crack or rust.
The ABS system relies on the brake light switch to know exactly when you are pressing the pedal. If this switch fails, the system may disable itself for safety and illuminate the ABS and traction control lights.
A simple electrical short, power surge, or aging component can blow the fuse or burn out the relay that supplies power to the ABS system.
The computer module that controls the anti-lock braking system can suffer from internal electrical failures, such as broken solder joints or fluid intrusion over time. This is a costly but less frequent failure.