The following fault symptoms may occur in conjunction with the independent/auxiliary heater:

• Independent/auxiliary heater will not start (combustion air blower cannot be heard)
  
• Independent/auxiliary heater switches off after one or several start attempts (combustion air blower can be heard but then switches off)
  

This may be attributed to a fault lock-out due to following statuses:

• 1.) Undervoltage cutout triggered
  
• 2.) Overheating protection function triggered
  
• 3.) Fault lock-out due to insufficient fuel
  

Under certain conditions, the following may provide a remedy to the individual fault symptoms:

• Re: 1.) Check battery status and charge by alternator (Attention: Repeatedly driving short distances can lead to problems; explain situation to customer accordingly)
  
• re. 2. and 3.) Clear fault lock-out via service function ”Unlock auxiliary heater” . If the auxiliary heating system does not receive any fuel , the auxiliary heater tries to start three times. If this does not succeed, the control unit is locked. Minimum tank contents are 8 litres of fuel. That is, with the fuel tank on reserve or low fill level, ensure flow of fuel. Check all hose lines for bends and leaks.
  

Information on unlocking independent/auxiliary heater:

• Either reset via the service function auxiliary heater faulty locking.
  
• Or manually. Switch on the independent/auxiliary heater at the switch. Within 60 seconds , cut off the power supply (terminal 30) by pulling the fuse and leave open for at least 2 seconds. Then switch off the independent/auxiliary heater and re-insert the fuse.
  

Important: It is not possible to activate the independent/auxiliary heater if a fault code for the independent/auxiliary heater is stored in the IHKA control unit (E38). In this case, first delete the IHKA fault code memory. Possible fault:

• 59 K-bus fault