The glow plug control module is a solid state device which operates the glow plugs. The temperature and the power consumption is controlled between the engine control module (ECM) and the glow plug control module within a wide range to suit the engine pre heating requirements. The ECM controls the glow plug control module with a pulse-width modulated (PWM) control circuit. The glow plug initial ON time will vary based on the system voltage and temperature. Lower temperatures cause longer ON times.

The ECM detects an open, short to ground, or a short to voltage on the glow plug module control circuit for greater than 0.5 s.

DTC P064C is a Type C DTCs.

DTC P064C is a Type C DTCs.

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

1. Ignition ON, observe the DTC information with a scan tool. DTC P064C should not set.
2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

1. Ignition OFF, disconnect the harness connector X1 at the K34 Glow Plug Control Module (GPCM).
2. Test for less than 5 Ω between the ground circuit terminal 3 (X1) and ground.

⇒	If greater than the specified range, test the ground circuit for an open/high resistance.

3. Connect a test lamp between the B+ circuit terminal 5 (X1) and ground.

⇒	If the test lamp is OFF, test the B+ circuit for a short to ground or an open/high resistance.

4. Ignition ON, connect a test lamp between the ignition circuit terminal 4 (X1) and ground.

⇒	If the test lamp is OFF, test the ignition circuit for a short to ground or an open/high resistance.

5. Test for less than 0.3 V between the control circuit terminal 2 (X1) and ground.

⇒	If greater than the specified range, test the signal circuit for a short to voltage.

6. Ignition OFF, disconnect the harness connector X2 at the K20 Engine Control Module (ECM).
7. Test for greater than 500 kΩ between the K34 Glow Plug Control Module (GPCM) control circuit terminal 2 (X1) and ground.

⇒	If less than the specified range, test the signal circuit for a short to ground.

8. Test for less than 5 Ω between the control circuit terminal 2 (X1) at the K34 Glow Plug Control Module (GPCM) harness connector and terminal 42 (X2) at the K20 Engine Control Module (ECM) harness connector.

⇒	If greater than the specified range, test the signal circuit for an open/high resistance.

9. If the circuit tests normal, replace the K34 Glow Plug Control Module (GPCM).
10. Verify the DTC does not reset.

⇒	If DTC is set, replace the K20 Engine Control Module (ECM).

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.