Control unit
â–¶ How to fix
Erase the fault code to unlock the control unit and test run the auxiliary heater.
What you'll see
No driver-visible symptom recorded.
System reaction
No system-reaction text recorded.
Diagnostic depth
Detection
The auxiliary heater control unit is locked because of too many occurrences of overheating or fault code 117 and the auxiliary heater has attempted to start.
Possible cause
Blocked air supply to the auxiliary heater, cold air. Blocked air vent from the auxiliary heater, heated air.Fault in the fuel supply. Fault in control unit or overheat sensor.