ABS Wheel Speed Sensor
What it is
An ABS sensor (wheel speed sensor) sits at each wheel and reads how fast that wheel is turning. The ABS and traction-control systems depend on it.
What it does
It tells the ABS module each wheel's speed so the system can detect lockup and pulse the brakes. A dirty or failed sensor disables ABS and lights the ABS/traction warning. These faults are stored as chassis (C-) codes, so they need an ABS-capable scanner — a basic engine reader will not show them.
Symptoms of failure
- ABS warning light (and often traction-control light)
- ABS or stability control disabled
- Speedometer glitches on cars that use these for road speed
- A C-code stored (read with an ABS-capable scanner)
- Pulsing brakes that should not pulse, or no ABS in slippery stops
Which vehicles need it
Every car with ABS. Dirt, metal debris and a damaged tone ring are the usual causes; rust-belt cars suffer most.
Replacement cost
| DIY (part only) | $20–$90 |
|---|---|
| At a shop (parts + labor) | $150–$400 |
| Replacement interval | No set interval — replace on failure; clean the sensor and tone ring first. |
| DIY difficulty | Easy–Moderate (DIY) — one bolt and connector, but the bolt often seizes |
| Recommended brands | Bosch, ACDelco, Dorman, OEM |
Where to buy the part
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Recommended products
Tools to diagnose it
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Frequently asked questions
Why do I need a special scanner for an ABS sensor?
ABS faults are stored as chassis (C-) codes, not the engine (P-) codes a basic OBD-II reader shows. You need an ABS-capable, all-system scanner to read which wheel sensor is at fault.
Can I still drive with the ABS light on?
Your normal brakes still work, so you can drive carefully, but you lose anti-lock and often traction control. Avoid hard stops in slippery conditions and fix it soon.