B0450
DTC B0449, B0450, B0451, or B0452
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 B0449 00
- Auxiliary Heater Blower Fan Circuit Range/Performance
DTC B0450 00
- Auxiliary Heater Blower Fan Circuit Low
DTC B0451 00
- Auxiliary Heater Blower Fan Circuit High
DTC B0452 00
- Auxiliary Heater Blower Fan Circuit Open
Diagnostic Fault Information
Circuit/System Description
The fuel operated heater uses a coolant heater blower motor to supply oxygen onto the combustion chamber so the air fuel mixture will ignite when the glow plug is activated.
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 Coolant Heater Blower Motor scan tool parameters. The scan tool parameters should display On when the heater is activated.
Component Testing
1. Ignition OFF, disconnect the 14- pin coolant heater module connector from the module.
2. Test the coolant heater blower motor 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 blower motor.
4. If the coolant heater blower motor tests normal, replace the coolant heater.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
* Heater Coolant Heater Glow Plug Replacement
* Heater Coolant Heater Replacement Verification Tests