Here is a instruction show you guide on how to diagnose and repair auxiliary heater system ATA 111 trouble code insufficient voltage problem.
The voltage has been too low. Below 20 V.
Fault in cable harness, battery or control unit.
The auxiliary heater was switched off because the voltage to the control unit was too low.
Check the voltage supply. Measuring points 1 and 9 in the connector from the auxiliary heater toward 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 connectors and wiring.
Check the positive and negative connections.
Clear the fault code and test run the auxiliary heater and vehicle.
For more information about Scania truck,please refer to:Scania Trouble Repair.