Insufficient voltage
â–¶ How to fix
Test the voltage across measuring points 1 and 8 in the connector on the vehicle cable harness. The measurement should not be different from the voltage value from the battery. If the voltage is above 20 V, renew the control unit. If the voltage is below 20 V, check the voltage supply. Check the wiring and connectors. Check the positive and negative connections. Erase 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 low.
Diagnostic depth
Detection
The voltage has been below 20 V.
Possible cause
Fault in the cable harness, battery or control unit.