WEBASTO FUEL BURNING HEATER (CONFIG 1) - System Overview
The fuel burning heater is a self contained unit manufactured by Webasto, which automatically maintains a minimum temperature in the vehicle by heating the water using fuel drawn from the vehicles main fuel Tank. The unit is manufactured with 2 distinctly different diagnostic communication protocols. Fuel Burning Heater with configuration 1 is optional fitted in several models of Land Rovers and the Rover 75 car, typically in cold climate countries.
SM038 - WEBASTO FUEL BURNING HEATER (CONFIG 1) - System Help file
Version 1.26

WEBASTO FUEL BURNING HEATER (CONFIG 1) - Known Fitments
Vehicle makes, models and variants known or believed to be using this vehicle system, required diagnostic lead and degree of known compatibility.

Vehicle Make Vehicle Model Vehicle Variant Diagnostic Lead
Land Rover Freelander Option after 2000 - Cold Climate Pack Black OBDII Lead
Land Rover Discovery II Cold Climate Pack Option Black OBDII Lead
Rover Rover 75 Cold Climate Option Black OBDII Lead

WEBASTO FUEL BURNING HEATER (CONFIG 1) - Physical Details

SM038 - WEBASTO FUEL BURNING HEATER (CONFIG 1) - Diagnostic Capabilities (Read Fault Codes)
Reads the fault code memory. The ECU can self detect up to 11 different problems with itself, its wiring and its associated sensors, storing the respective code if it detects any malfunction or reading outside of pre defined acceptable limits. Not all stored faults may cause the fault warning lamp to illuminate.

SM038 - WEBASTO FUEL BURNING HEATER (CONFIG 1) - Diagnostic Capabilities (Clear Fault Codes)
Clears the fault code memory.

SM038 - WEBASTO FUEL BURNING HEATER (CONFIG 1) - Diagnostic Capabilities (Settings)
Values, configuration settings, and other stored information which can be read from the ECU, edited and then rewritten back. Read settings can also be stored as a standard HTML page for reference. These pages can then later be re loaded and re written back to the ECU. Please note that some values may be read only due to the fact that they are supplied from the ECUs ROM or are internally calculated.

  • Part Number: This is the manufacturer's part number for the ECU.
  • Hardware Number: This is the hardware version which denotes the processor and circuit board type.
  • Software Number: This is a number which relates to the software programmed in the processor of the ECU.
  • Supplier Number: This is a number which defines the supplier using a standard look up list of supplier of ECU manufacturer.
  • Diagnostic Index: This is a number that indicates the diagnostic capabilities support level.
  • Bus Index: This is a number that indicates the bus communication support level, the vehicle communication buses.
  • Coding Index: This is a number which denotes the layout of the options within the EEPROM of the ECU and denotes which coding map should be used to program the ECU with.
  • Day of Build: The day the unit was built.
  • Month of Build: This is the month in which the unit was built.
  • Year of Build: This is the year in which the unit was built.

SM038 - WEBASTO FUEL BURNING HEATER (CONFIG 1) - Diagnostic Capabilities (Inputs)
Realtime live display of the information the electronic control unit of the selected vehicle system is currently deriving from its input sensors.

  • CO2: This shows the figure set during production to ensure that the heater has a CO2 value between 69 and 88.
  • Coolant Temperature: This shows the coolant temperature as measured by the ECU using the sensor fitted on the control board. The temperature measured is 10C lower than that measured by the coolant sensor used by the engine management ECM.
  • Combustion Chamber Temperature: This shows the combustion chamber temperature measured by the ECU. Once the heater is running, the resistance of the glow plug is used to measure the temperature of the combustion process. The reading will show 'N/A' until the heater starts its burn cycle.
  • Battery Voltage: Displays the input voltage as measured by the ECU at pin 1. If the supply voltage is less than the low voltage limit for greater than 20 seconds, operation of the burner will be inhibited to prevent flattening the battery.
  • Low Voltage Limit: Displays the minimum permissible input voltage as measured by the ECU at pin 1. If the supply voltage is less than this low voltage limit for greater than 20 seconds, operation of the burner will be inhibited to prevent flattening the battery.
  • Combustion Air Fan Power: Displays the combustion air fan power. The combustion air fan ramps up from 0% to approximately 90% (+/- 10%) when the heater is working at full load. The heater runs at full load until the coolant temperature, as measured by the onboard sensor reaches 70C. The heater then switches the to half load with a combustion air fan power of approximately 50% until the coolant temperature reaches 75C when the heater switches off. If the coolant temperature then drops to 66C the heater restarts at half load. If the coolant temperature drops below 61C the heater switches back to full load.
  • Dosing Pump Frequency: Displays the dosing pump frequency. The dosing pump frequency is 2.6Hz when the heater is working at full load. The heater runs at full load until the coolant temperature, as measured by the onboard sensor reaches 70C. The heater then switches to half load with a dosing pump frequency of 1,3Hz until the coolant temperature reaches 75C when the heater switches off. If the coolant temperature then drops to 66C, the heater restarts at half load. If the coolant temperature drops below 61C the heater switches back to full load. The reading will show 'N/A' until the heater starts its burn cycle.
  • Combustion Air Fan: This displays the state of the combustion air fan as seen by the ECU. When 'OFF', the combustion fan is not running. When 'ON', the combustion fan is blowing air into the burner to achieve the correct fuel air mix.
  • Glow plug: This displays the state of the glow plug as seen by the ECU. The glow plug has two functions. It is used to ignite the fuel to start the burner. Once the heater is running it is used to detect the flame and measure the temperature of the combustion chamber. When 'OFF', the glow plug is being used to measure the temperature of the combustion process. When 'ON', the glow plug is being heated to ignite the fuel.
  • Coolant Pump: This displays the state of the coolant pump as seen by the ECU. When 'OFF', the coolant pump is not running. When 'ON', the coolant pump is circulating coolant through the heater.
  • Dosing Pump: This displays the state of the dosing pump as seen by the ECU. When 'OFF', the dosing pump is not running. When 'CYCLING', the dosing pump is injecting fuel into the heater.
  • Flame Status: This displays the state of the combustion chamber as seen by the ECU. Once the heater is running, the glow plug is used to detect the flame status. 'NO FLAME' indicates that no flame is detected in the combustion chamber. 'PRESENT' indicates that a flame is detected in the combustion chamber.
  • Heater Error Lockout: This displays the status of the overheat lockout heater protection system. If the heater ECU detects three system errors it shuts the heater down for self protection. Once the faults have been corrected, the heater can be re-activated by using the 'PRIME SYSTEM' function in the 'Other' menu. 'UNLOCKED' indicates that the fuel burning heater is able to function. 'LOCKED' indicates that the fuel burning heater has been shut down due to multiple system errors.

SM038 - WEBASTO FUEL BURNING HEATER (CONFIG 1) - Diagnostic Capabilities (Outputs)
Outputs that can be pulsed. To repeat the action, click again on pulse button.

  • Fuel Burning Heater: CAUTION: Do not turn the FBH on for more than a max of 8.5 min.
  • Coolant pump CAUTION: CAUTION: Do not turn the Coolant Pump on for more than a max of 30 sec.
  • Glow Plug CAUTION: CAUTION: Do not turn the Glow Plug on for more than a max of 10 sec.
  • Combustion Air Fan CAUTION: CAUTION: Do not leave the Combustion Air Fan on for more than a max of 30 sec.
  • Dosing Pump CAUTION: CAUTION: Do not turn the Dosing Pump on for more than a max of 30 sec.