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DTC P064C - LNP or LNQ

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 Descriptor

DTC P064C 00: Glow Plug Control Module Performance

Circuit/System Description

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.

Conditions for Running the DTC

    • The ignition is ON.
    • The ignition voltage is between 9-16 V.
    • The DTCs run once per ignition cycle when the above conditions are met.

Conditions for Setting the DTC

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.

Action Taken When the DTC Sets

DTC P064C 00 is a Type C DTC.

Conditions for Clearing the DTC

DTC P064C 00 is a Type C DTC.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Ignition ON, observe the DTC information with a scan tool. DTC P064C 00 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.

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector X1 at the K34 Glow Plug Control Module.
  2. Test for less than 5 Ω between the ground circuit terminal 3 X1 and ground.
  3. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Connect a test lamp between the B+ circuit terminal 5 X1 and ground.
  5. If the test lamp is OFF, test the B+ circuit for a short to ground or an open/high resistance.
  6. Ignition ON, connect a test lamp between the ignition circuit terminal 4 X1 and ground.
  7. If the test lamp is OFF, test the ignition circuit for a short to ground or an open/high resistance.
  8. Ignition OFF, disconnect the harness connector X2 at the K20 Engine Control Module.
  9. Ignition ON, test for less than 0.3 V between the control circuit terminal 2 X1 and ground.
  10. If greater than the specified range, test the signal circuit for a short to voltage.
  11. Ignition OFF, test for greater than 500 kΩ between the K34 Glow Plug Control Module control circuit terminal 2 X1 and ground.
  12. If less than the specified range, test the signal circuit for a short to ground.
  13. Test for less than 5 Ω between the control circuit terminal 2 X1 at the K34 Glow Plug Control Module harness connector and terminal 46 X2 at the K20 Engine Control Module harness connector.
  14. If greater than the specified range, test the signal circuit for an open/high resistance.
  15. If the circuit tests normal, replace the K34 Glow Plug Control Module.
  16. Verify the DTC does not reset.
  17. If DTC is set, replace the K20 Engine Control Module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Glow Plug Controller Replacement
    • Control Module References for ECM replacement, setup, and programming
   


© Copyright Chevrolet. All rights reserved
   


© Copyright Chevrolet. All rights reserved