Overvoltage
â–¶ How to fix
Test the voltage across measuring points 1 and 8 in the connector on the vehicle cable harness. If the voltage is above 30 V, check the alternator. If the voltage is below 30 V, renew the control unit. Check connectors and wiring. Delete the fault code and test run the auxiliary heater and vehicle.
What you'll see
No driver-visible symptom recorded.
System reaction
The auxiliary heater has been shut off due to the voltage to the control unit having been too high.
Diagnostic depth
Detection
The voltage has been too high.
Possible cause
Fault in the power supply or control unit.