C0235
Wheel Speed Sensor Signal Erratic
The ABS control module has detected an erratic wheel speed sensor signal — sudden jumps or dropouts compared to the other wheels. Typical causes are a damaged tone ring or a loose sensor.
- Check engine light: Not always
- Emissions related: No
- Repair difficulty: medium
Symptoms
- ABS warning light on
- ESC/stability control deactivated
- Possible reduced brake assist
- Speedometer may behave erratically
Common causes
Ordered by how often each turns out to be the cause.
- Tone ring damaged or contaminated with metal debrisCommon
- Wheel speed sensor loose in housingPossible
- Excessive hub bearing playLess likely
Parts involved
- Wheel Speed Sensor
- Tone Ring
- ABS Control Module
C0235 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.