B0478

DTC B0478

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 for minimum power

DIAGNOSTIC FAULT INFORMATION






IMPORTANT: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview

CIRCUIT/SYSTEM DESCRIPTION
The fuel operated heater uses a coolant heater combustion sensor to monitor flame temperature.

CONDITIONS FOR RUNNING THE DTC
Engine 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 combustion sensor scan tool parameter. The scan tool parameter should display between 0.09-4.9 volts.

COMPONENT TESTING
1. Ignition OFF, disconnect the 14-pin coolant heater module connector from the module.
2. Test the coolant heater combustion sensor 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 sensor.
4. If the coolant heater combustion sensor tests normal, replace the coolant heater.

REPAIR INSTRUCTIONS

IMPORTANT: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Cell link coolant heater combustion sensor

Cell link replace the coolant heater