Symptom guide
ABS Light On
What an ABS warning light means and why normal braking may not tell the whole story.
Quick answer
An ABS light commonly comes from wheel speed sensors, wiring, tone rings, low voltage, or ABS module faults.
Most likely causes
- Wheel speed sensor fault
- Damaged sensor wiring
- Bad wheel bearing encoder
- Low battery voltage
- ABS module issue
Basic driver checks
- Check if traction control light is also on.
- Notice if the light came after tire, brake, or hub work.
- Scan with a tool that reads ABS codes.
- Check tire sizes match.
DIY diagnostic path
- A basic engine scanner may not read ABS codes.
- Inspect visible wheel sensor wires.
- Do not ignore brake warning light with ABS light.
- Check battery health if multiple lights appear.
Common mistakes
- Assuming ABS light is a pad wear light
- Ignoring mismatched tire size
- Clearing codes without fixing wiring
What to tell the mechanic
Ask for ABS module codes and wheel speed data, not just an engine scan.