C0660Left Rear Wheel Speed Sensor B Range/Performance
- Generic OBD-II code · Chassis
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- C0660 means the wiring of sensor B at the left rear tests good, yet its output fails to act like a wheel speed: it may vanish at speed, jump or show an odd pulse pattern. No published service data defines the check. Mounting is a common reason. NXP's application note for magnetoresistive speed sensors explains that a sensor placed off-centre to its target delivers a weaker signal with extra offset, which shows up as a duty cycle well away from 50 %, while a tilt below about 4° hardly matters. The KMI25 even reports the problem itself: one bit of its AK protocol is set when the magnetic field becomes too weak for normal operation. GM's keyword list PIP5094 contains C0660 only as an older GM number with a different meaning.
- What you may notice
- Warning only appears while driving, often above a certain speed
- Assistance functions withdrawn while ABS on sensor A continues
- Likely causes
- LikelySensor seated off-centre or too far from its encoder
- PossibleEncoder ring worn, dirty or weakly magnetised
- RareSensor B degraded internally
- 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.