The glow control system is operated when the engine coolant temperature is low, which allows easier engine starting. If the ignition switch is turned ON when the engine coolant temperature is low, the engine control module (ECM) illuminates the glow indicator lamp and turns ON the glow plugs. After a fixed time passes, the ECM turns OFF the glow indicator lamp and the glow plugs. The glow plug control module (GPCM) has the ability to perform internal diagnostics for voltage and the output state of the glow plugs. If the GPCM detects a GPCM system voltage error, the GPCM will send a message to the ECM via the controller area network (CAN) communication bus and sets this DTC.

Either of following condition is met:

DTC P064C is a Type B DTC.

DTC P064C is a Type B DTC.

A charging system condition may set this DTC.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Verify the integrity of the GPCM power supply or CAN communication circuit by inspecting for the following conditions:

Important: You must perform Circuit/System Verification before proceeding with Circuit/System Testing.

1. Disconnect the GPCM harness X1 or X2 connector.
2. Ignition ON, verify that a test lamp illuminates between the GPCM battery voltage feed circuit and ground.

⇒	If the test lamp does not illuminate, test the battery voltage feed circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the GPCM.

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

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.