Lost Communication With Rear HVAC Air Cutoff Actuator
The vehicle bus reports loss of communication with smart rear HVAC air cutoff actuator (shuts the rear duct entirely off). Cutoff cannot be commanded; rear airflow stays in last-known position.
Affected components
- Rear hvac cutoff actuator
- Vehicle bus wiring
Common causes
- High likelihood: Bus wiring open or shorted
- Medium likelihood: Module without power or ground
- Medium likelihood: Module failed
Possible symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Diagnostic notes
- A drive cycle may be required after repair
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.