Auxiliary climate control module
NOTE: If a unit or component is likely to fail and the vehicle is still under manufacturer's warranty, refer to the warranty manual before replacing the component (section B1.2) or determine if there is any previously approved special program in operation.
NOTE: Universal Scan Tools may not read the listed codes or may only read 5-digit codes. Match the 5 digits from the scan tool with the first 5 digits of the 7-digit code listed to identify the problem (the last 2 digits give additional information read by the diagnostic system approved by the manufacturer).
NOTE: Always use a digital multimeter when performing voltage or resistance tests (DMM) accurate to three decimal places and with a valid calibration certificate. When testing resistance, be sure to consider the resistance of the DMM leads.
NOTE: Before starting diagnostic programs using troubleshooting tests, check and correct major problems.
NOTE: Inspect the connectors for signs of water intrusion and their pins for damage and (or) traces of corrosion.
NOTE: If DTCs are logged and there is no problem after performing troubleshooting tests, an intermittent problem may be the cause. Be sure to check for loose connections and corroded contacts.
Description and operation
For a detailed description of the operation of the fuel-fired auxiliary heater control system, refer to the relevant system description and operation section of the repair manual. For more information, see chapter: Auxiliary Fuel Heater (412-02 Additional climate control, Description and principle of operation).
NOTE: Function «self-tests on request» can be called via tab «DTC Monitor» in the manufacturer's approved diagnostic system.
DTC | Description | Possible reasons | Action |
B1D22-11 | Coolant Temperature Sensor Circuit Short to Ground | Internal malfunction of the oil-fired additional heater temperature sensor | |
B1D22-15 | Engine Coolant Temperature Sensor Circuit Short to Battery Positive or Open Circuit | Internal malfunction of the oil-fired additional heater temperature sensor | |
B1D23-13 | Overheating sensor: open circuit | Internal malfunction of the oil-fired additional heater temperature sensor | |
B1D24-11 | Glow Plug Circuit Short to Ground | Internal Glow Plug Fault for Oil-Fired Auxiliary Heater | |
B1D24-15 | Glow plug circuit short to battery positive or open circuit | Internal Glow Plug Fault for Oil-Fired Auxiliary Heater | |
B1D25-11 | Heater Fuel Pump Circuit Short to Ground | ||
B1D25-15 | Heater Fuel Pump Circuit Short to Battery Positive or Open Circuit | ||
B1D26-11 | Combustion air supply fan circuit short to ground | Fuel Fired Auxiliary Heater Control Module Malfunction | |
B1D26-15 | Combustion air blower circuit short to battery positive or open circuit | Fuel Fired Auxiliary Heater Control Module Malfunction | |
B1D26-92 | Combustion air blower not working or not working properly | Fuel Fired Auxiliary Heater Control Module Malfunction | |
B1D26-93 | Combustion chamber fan: not working | Fuel Fired Auxiliary Heater Control Module Malfunction | |
B1D27-11 | Heater coolant pump circuit short to ground | ||
B1D27-15 | Heater Coolant Pump Circuit Short to Battery Positive or Open Circuit | ||
B1D28-11 | Fuel pre-heater - short circuit to ground | NOTE: Preheating is done by a glow plug. | |
B1D28-15 | Fuel preheater short to battery positive or open circuit | NOTE: Preheating is done by a glow plug. | |
B1D29-93 | Startup does not occur even after a second attempt: does not work | ||
B1D30-93 | Unable to run in test mode: not working | ||
B1D31-94 | Flame detected before normal operation: Unexpected action | NOTE: The glow plug and flame sensor are one unit. | |
B1D32-92 | Repeated flame interruption during the preheat cycle - does not work or does not work correctly | ||
B1D33-92 | Flame interruption during normal operation: does not work or does not work correctly | ||
B1D34-68 | Heater in blocking mode: event information | Oil auxiliary heater system malfunction | NOTE: For information only, resolve other stored oil fired auxiliary heater DTCs before troubleshooting this code. |
B1D63-11 | External control relay - short circuit to ground | Fuel Fired Auxiliary Heater Control Module Malfunction | |
B1D63-15 | External control relay - circuit short to battery or open circuit | Fuel Fired Auxiliary Heater Control Module Malfunction | |
U0010-00 | Medium speed CAN communication bus: no subtype information | Disabling the Medium Speed CAN Communication Bus | Perform a CAN bus continuity test using the manufacturer approved diagnostic system. |
U0028-08 | Communication bus A: bus signal/message failure | Perform a CAN bus continuity test using the manufacturer approved diagnostic system. | |
U0300-00 | Internal control unit software incompatibility: No subtype information | Fuel fired auxiliary heater not configured or configured incorrectly | Using the manufacturer approved diagnostic system, reprogram the oil-fired auxiliary heater module (Unit Programming/Set Up Existing Unit/Auxiliary Heater Control Unit) |
U1A37-87 | Bus signal/collision message failure: no message | Collision signal received on CAN network | NOTE: Event Information: A collision has been registered in the SRS control unit. |
U2101-00 | Incompatible control unit configuration: No subtype information | ||
U3000-16 | Control unit: circuit voltage below threshold | ||
U3000-17 | Control unit: circuit voltage above threshold | ||
U3000-43 | Control unit: special memory failure | Fuel Fired Auxiliary Heater Control Module Malfunction | |
U3000-49 | Control unit: internal malfunction of the electronic equipment | Fuel Fired Auxiliary Heater Control Module Malfunction | |
U3003-62 | Battery voltage: signal comparison error | More than 2 V difference between fuel-fired auxiliary heater supply and battery voltage value reported via CAN bus |
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