U0660Lost Communication With Left Rear Temperature Actuator B
- Generic OBD-II code · Network
- How the car detects it
- Temperature actuator B is the second door for the same rear left zone that A serves. Where a rear zone uses two doors, one typically sets the split between cold and heated air and the other trims the mix further downstream, like the downstream rear door in Hanon's US 11,305,608; makers do not publish which letter goes to which. U0660 means the climate master gets no answer from actuator B over its LIN line. There is no public maker document for U0660; GM's 23-NA-206 lists only the A actuator on the left rear. Because A still answers, the rear left zone usually keeps some control: temperatures can be reached but overshoot, lag or sit a few degrees off. B alone missing is a narrow fault that points to that actuator or its own branch of wiring.
- What you may notice
- Rear left temperature drifts or overshoots the set value
- Rear left zone reacts slowly to temperature changes
- Likely causes
- LikelyActuator B electronics or motor failed
- PossibleFault in the wiring branch or plug that only actuator B uses
- RareReplacement actuator not assigned or calibrated by the scan tool
- Repair
- Hard · Usually a job for a workshop.Typical cost: €60 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.