Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptors
DTC B0440 00 : Auxiliary Heater Glow Plug Circuit LowDTC B0441 00 : Auxiliary Heater Glow Plug Circuit High
DTC B0442 00 : Auxiliary Heater Glow Plug Circuit Open
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Heater Glow Plug Supply Voltage Circuit | B0440 00 | B0442 00 | B0441 00 | B0440 00, B0441 00, B0442 00 |
Heater Glow Plug Low Reference Circuit | - | B0442 00 | B0441 00 | B0440 00, B0441 00, B0442 00 |
Circuit/System Description
The fuel operated heater uses an auxiliary heater glow plug to increase the temperature in the combustion chamber to a temperature that is necessary to ignite the air fuel mixture. Once a stable flame has formed, the glow plug will turn OFF.
Conditions for Running the DTC
Engine is running.
Conditions for Setting the DTC
Fuel operated heater has recognized out of range condition for more than 2.5 seconds.
Action Taken When the DTC Sets
Fuel operated heater is disabled.
Conditions for Clearing the DTC
DTC must be cleared with a scan tool.
Reference Information
Schematic Reference
Connector End View Reference
Cooling System Connector End Views
Electrical Information Reference
Scan Tool Reference
Circuit/System Verification
Start the vehicle. Observe the Auxiliary Glow Plug On scan tool parameter. When the glow plug is activated, the scan tool should read near battery voltage.
Component Testing
- Ignition OFF, disconnect the 14-pin coolant heater module connector at the module.
- Test the coolant heater glow plug resistance.
- Compare the readings with the Temperature vs Resistance table and verify that the resistance is within 5 percent of the specification.
- If the glow plug tests normal, replace the coolant heater.
| ⇒ | If the resistance vs temperature reading is not within 5 percent, replace the coolant heater glow plug. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
