Brakes
Wheel Speed Sensor
The wheel speed sensor tells the ABS and stability systems how fast each wheel is turning.
Free guide
Advertisement
Brake system flow
Interactive — tap a partTap a part to see how it fits in the system.
What it does
- Reads a toothed ring at each wheel
- Feeds speed data to ABS/ESP
- Also used for the speedometer and traction control
When it fails
- ABS/ESP warning light
- Speedometer dead or erratic
- ABS does not engage
- C0xxx codes
How to diagnose
- Measure sensor resistance and signal
- Check the wiring and connector
- Inspect the tone ring for damage
- Compare live wheel speeds
Maintenance
- Keep sensors and rings clean
- Fix wiring before corrosion spreads
Use the diagnosis order. When a part fails, confirm each hypothesis with measurements before replacing anything — codes and symptoms overlap.
Related part
ABS Module & Pump
The ABS module reads wheel speeds and modulates brake pressure to stop wheels from locking.