B0441

DTC B0440, B0441, or B0442

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* 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 Low

DTC B0441 00
- Auxiliary Heater Glow Plug Circuit High

DTC B0442 00
- Auxiliary Heater Glow Plug Circuit Open

Diagnostic Fault Information







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.

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

1. Ignition OFF, disconnect the 14 pin coolant heater module connector at the module.
2. Test the coolant heater glow plug resistance.
3. Compare the readings with the Temperature vs Resistance table and verify that the resistance is within 5 percent of the specification.

• If the resistance vs temperature reading is not within 5 percent, replace the coolant heater glow plug.

4. If the glow plug tests normal, replace the coolant heater.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

* Heater Coolant Heater Glow Plug Replacement
* Heater Coolant Heater Replacement