B0465

DTC B0465, B0467, or B0478

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 B0465 00

-
Auxiliary Heater Flame Sensor Circuit Low

DTC B0467 00

-
Auxiliary Heater Flame Sensor Circuit Open

DTC B0478 00

-
Flame Off From Minimum Power

Diagnostic Fault Information






Circuit/System Description

The fuel operated coolant heater uses a combustion sensor to monitor flame temperature.

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 more 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

1. Ignition ON, verify DTC B1424 is not set.

• If the DTC is set, refer to DTC B1424 (TDM) Engine Electrical TDMDTC B1424 (Coolant Heater) Engine Electrical Coolant Heater.

2. Engine running, observe the scan tool Flame Temperature Sensor parameter. The parameter should be between 0.09-4.9 volts.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the combustion sensor.

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

• If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the coolant heater.

3. Ignition ON, verify the scan tool Flame Temperature Sensor parameter is greater than 4.5 volts.

• If less than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the coolant heater.

4. Install a 3A fused jumper wire between the signal circuit and the low reference circuit. Verify the scan tool Flame Temperature Sensor parameter is less than 0.5 volts.

• If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the coolant heater.

5. If all circuits test normal, test or replace the combustion sensor.

Repair Instructions

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

* Heater Coolant Heater Combustion Sensor Replacement Heater Coolant Heater Combustion Sensor Replacement

* Heater Coolant Heater Replacement Heater Coolant Heater Replacement