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DTC 71 or 72

DTC 71 or 72

Diagnostic Instructions


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

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

• Diagnostic Procedure Instructions provides an overview of each diagnostic category.


DTC Descriptors

DTC 71

Parking Heater Overheat Sensor Circuit Open

DTC 72

Parking Heater Overheat Sensor Circuit Low or Circuit High

Diagnostic Fault Information

Circuit Short to Ground Open/High Resistance Short to Voltage Signal Performance
Parking Heater Overheat Sensor Signal

72

71

72

-

Parking Heater Overheat Sensor Low Reference

-

71

72

-



Circuit/System Description

The parking heater uses an overheat sensor to protect the module for over temperature condition.

Conditions for Running the DTC

Ignition OFF. Battery voltage must be between 10-15 V.

Conditions for Setting the DTC

parking heater has recognized out of range condition for more than 2.5 s.

Action Taken When the DTC Sets

The parking heater will lock.

Conditions for Clearing the DTC

DTC must be cleared with the remote control.

Reference Information

Schematic Reference

HVAC Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Fuel Operated Heater Description and Operation

Electrical Information Reference


• Circuit Testing

• Connector Repairs

• Testing for Intermittent Conditions and Poor Connections

• Wiring Repairs


Circuit/System Verification

Ignition OFF, command the parking heater ON and OFF with the remote control. Verify the parking heater turns ON and OFF with no DTCs.

Circuit/System Testing


1. Ignition OFF, separate the K87 Parking Heater Control Module from the X150 Parking Heater Harness & Parking Heater Assembly Harness.

2. Test the B169 Parking Heater Overheat Sensor by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the Fuel Operated Heater Sensor Resistance Table and verify that the resistance is within 5% of the specification.

3. If not within the specified range, replace the B169 Parking Heater Overheat Sensor.

4. If the B169 Parking Heater Overheat Sensor tests normal, replace the K87 Parking Heater Control Module.


Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.