C0656Left Front Wheel Speed Sensor B Correlation
- Generic OBD-II code · Chassis
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- C0656 flags a mismatch between the B signal at the left front hub and the values it is checked against, typically sensor A on the same hub, while the circuit itself tests good. No carmaker publishes this code or its limits. Two patent designs show what such a comparison can catch. Continental Teves placed two magnetoresistive paths of different sensitivity in one housing; a comparator inside the sensor checks whether both deliver the same frequency, because a disturbed path can flip and even double the reading. Audi proposed pairing an active Hall sensor with a passive inductive one on the same pulse wheel, so that a supply failure cannot silence both. Likely causes: a damaged encoder, a sensor sitting too far from its encoder, mixed-up parts.
- What you may notice
- Warning for brake or driver assistance system
- Automated or redundant brake functions withdrawn, ABS usually still active
- Likely causes
- LikelySensor not seated correctly, air gap out of tolerance
- PossibleDamaged, dirty or partly demagnetized encoder ring
- RareSensor of a different type or side fitted
- Repair
- Medium · Usually a job for a workshop.Typical cost: €60 – €700
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.