C066BRight Rear 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
- The second right rear speed value is electrically fine but disagrees with its references. No carmaker documents C066B or its limits. A Ford patent shows a check that suits a driven rear axle: the right rear speed is calculated as twice the output shaft speed divided by the axle ratio, minus the measured left rear speed. If measured and calculated values differ beyond a tolerance on consecutive passes or for more than 0.2 s, the fault is registered, and the calculated value stands in meanwhile. The tolerance can be tightened with lateral acceleration, and the side under more load gets the closer look. Bosch describes a similar estimate from the three other wheels, validated against the gearbox output. Wrong tyre sizes or a damaged encoder can trigger such a mismatch.
- What you may notice
- Warning after a fast or long drive
- Traction or stability functions temporarily reduced
- Likely causes
- LikelyMismatched tyre size or tread depth at the right rear
- PossibleEncoder with missing or extra pulses
- RareAxle ratio or tyre data in the module not matching the vehicle
- Repair
- Medium · Usually a job for a workshop.Typical cost: €60 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.