B0442

DTC B0440, B0441, or B0442

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.

* Diagnostic Procedure Instructions 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 coolant heater uses a heater glow plug to increase the temperature in the combustion chamber to a temperature that will 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

The fuel operated coolant heater has recognized out of range condition for greater than 2.5 seconds.

Action Taken When the DTC Sets

The fuel operated coolant heater is disabled.

Conditions for Clearing the DTC

* A current DTC will clear when the conditions for setting the DTC are no longer present.

* A history DTC will clear after 40 malfunction-free ignition cycles.

Reference Information

Schematic Reference

HVAC Schematics Electrical DiagramsHVAC Schematics Electrical Diagrams

Connector End View Reference

Component Connector End Views 1-2 Shift Solenoid (SS) Valve (M30)

Description and Operation

Air Temperature Description and Operation Air Temperature

Electrical Information Reference

* Circuit Testing Circuit Testing

* Connector Repairs Connector Repairs

* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections

* Wiring Repairs Wiring Repairs

Scan Tool Reference

Control Module References Control Module References for scan tool information

Circuit/System Verification

Engine running, observe the scan tool Glow Plug Command parameter. When the glow plug is activated, the scan tool should display On.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the glow plug.

2. Ignition OFF, test for less than 5 ohms between the low reference circuit terminal and ground.

• If greater than the specified range, replace the coolant heater.

3. Install a test lamp between the control circuit terminal and low reference circuit terminal.

4. Ignition ON, command the glow plug ON and OFF using a scan tool. Verify the test lamp turns ON and OFF with each command.

• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the coolant heater.

• If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the coolant heater.

5. If all circuits test normal, test or replace the glow plug.

Repair Instructions

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

* Heater Coolant Heater Glow Plug Replacement Service and Repair

* Heater Coolant Heater Replacement Heater Coolant Heater Replacement