B0455

DTC B0455 or B0457

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 provide an overview of each diagnostic category.

DTC Descriptors

DTC B0455 00
- Auxiliary Heater Coolant Sensor Circuit Low

DTC B0457 00
- Auxiliary Heater Coolant Sensor Circuit Open

Diagnostic Fault Information

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 an auxiliary heater coolant sensor to measure the coolant temperature.

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 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 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 sensor tests normal, replace the coolant heater.

Repair Instructions

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

Heater Coolant Heater Replacement