C0238
Speed Wheel-to-Wheel Mismatch
The ABS control module has detected an implausible speed difference between wheels that cannot be explained by cornering. This typically points to one suspect sensor, mismatched tyre sizes or a damaged tone ring.
- 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.
- Tyre sizes or wear levels do not match across axlesCommon
- Tone ring missing teeth on one wheelPossible
- Wheel speed sensor degradedLess likely
Parts involved
- Wheel Speed Sensor
- Tone Ring
- Tires
- ABS Control Module
C0238 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.