VIN 6

DTC P064C

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

DTC Descriptor
DTC P064C
- Glow Plug Module Control Performance

Diagnostic Fault Information





Typical Scan Tool Data





Circuit/System Description

The glow plug control module (GPCM) has the ability to perform internal diagnostics for voltage and output state of the glow plugs. The GPCM will send a message to the engine control module (ECM) to set this DTC.

Conditions for Running the DTC

* The ignition is ON.
* DTC P064C runs continuously.

Conditions for Setting the DTC

The GPCM detects a variation between the main battery supply to the GPCM and battery supply to the ECM, or an internal condition for 3 second.

Action Taken When the DTC Sets

DTC P064C is a Type B DTC.

Conditions for Clearing the DTC

DTC P064C is a Type B DTC.

Diagnostic Aids

Poor or improper connection of the B+ cable at the GPCM terminal X1 may cause this DTC to set.

Reference Information
Schematic Reference

Engine Controls Schematics ([1][2]Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector End Views By Name)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Verification

1. Engine running, accessories OFF, measure and record the battery voltage at the battery terminals. The voltage should be between 12.6-15.0 V.

• If not within the specified range, refer to Charging System Test (Charging System Test).

2. Verify the scan tool ECM Ignition 1 Signal parameter reading is between 12.6-15.0 V.
3. Verify the scan tool GPCM Ignition 1 Signal parameter reading is between 12.6-15.0 V.
4. Engine running, observe the DTC information with a scan tool. DTC P064C should not set.
5. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Circuit/System Testing

1. Ignition OFF, disconnect the X1 harness connector at the glow plug control module.
2. Measure and record the voltage between the battery positive voltage circuit terminal 1 of the X1 harness connector and ground. The voltage should be B+.

• If voltage is not B+, repair the open or high resistance in the battery positive voltage circuit.

3. Ignition OFF, disconnect the X2 harness connector at the GPCM.
4. Ignition ON, measure and record the voltage between the ignition 1 voltage circuit terminal 52 and ground.

• If voltage is not B+, test the ignition 1 voltage circuit for a short to ground or an open/high resistance.

5. Ignition ON, measure and record the voltage between the ignition 0 voltage circuit terminal 53 and ground.

• If voltage is not B+, test the ignition 0 voltage circuit for a short to ground or an open/high resistance.

6. If all circuits test normal, replace the GPCM.

Repair Instructions

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

Control Module References (Programming and Relearning) for GPCM replacement, setup, and programming