PRE-RELEASE
DTC 53 or 56
| DTC 53 or 56 |
| Diagnostic Instructions |
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Perform the
Diagnostic System Check - Vehicle
prior to using this diagnostic procedure.
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Review
Strategy Based Diagnosis
for an overview of the diagnostic approach.
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Diagnostic Procedure Instructions
provides an overview of each diagnostic category.
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| DTC Descriptors |
DTC 53
Parking Heater Combustion Aborted - Control Stage Large
DTC 56
Parking Heater Combustion Aborted - Control Stage Small
| Circuit/System Description |
The parking heater does not heat up instantly. It must go through a self test and start up procedure before normal operation. The parking heater depends on the fuel pump to deliver enough fuel in a timely manner. The electronic control module inside the heater determines when to turn on the fuel pump and the glow plug by monitoring coolant temperature and combustion temperature. The combustion sensor disables the glow plug once combustion is established and aborts the startup process if combustion is not established.
| Conditions for Running the DTC |
Ignition OFF. Battery voltage must be between 10-15 V.
| Conditions for Setting the DTC |
Before every start of the heater, the operation of the individual components is tested.
| Action Taken When the DTC Sets |
The parking heater will lock.
| Conditions for Clearing the DTC |
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A current DTC will clear if the next start procedure is successful.
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DTC must be cleared with the remote control.
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| 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
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Circuit Testing
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Connector Repairs
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Testing for Intermittent Conditions and Poor Connections
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Wiring Repairs
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| 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. |
Check the G26 Parking Heater Fuel Pump and filter for constrictions or lack of fuel. Refer to Fuel Pump Test.
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| 2. |
If the fuel filter is dirty, clean or replace the filter.
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| 3. |
Check exhaust and intake air manifolds for obstructions or improper location.
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| 4. |
Check the B167 Parking Heater Combustion Sensor for values out of range. Refer to Combustion Sensor Test.
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| 5. |
If everything tests normal, replace the K87 Parking Heater Control Module.
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| Component Testing |
Fuel Pump Test
| 1. |
Ignition OFF, parking heater OFF, disconnect the fuel line at the K87 Parking Heater Control Module.
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| 2. |
Turn the parking heater ON and ensure the fuel flows in an even, bubble-free stream.
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| 3. |
Cycle the parking heater OFF and ON and record the amount of fuel that flows in 90 s. The fuel pump should flow 10.7-11.9 ccm (0.362-0.402 oz.) in 90 s.
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| 4. |
If not within the specified range, replace the G26 Parking Heater Fuel Pump.
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Combustion Sensor Test
| 1. |
Ignition OFF, parking heater OFF, separate the K87 Parking Heater Control Module from the X150 Parking Heater Harness & Parking Heater Assembly Harness.
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| 2. |
Test the B167 Parking Heater Combustion 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.
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| 3. |
If not within the specified range, replace the B167 Parking Heater Combustion Sensor.
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| Repair Instructions |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
