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Test Procedure

  1. AF1 PRELIMINARY DIAGNOSIS 
    NOTE: If DTCs P0670 and P0683 are present, carry out DTC P0670 diagnosis before diagnosing DTC P0683.
    • Ignition OFF.
    • Carry out a visual inspection.
    • Ignition ON, engine OFF.
    • Record the freeze frame data.
    • Carry out the KOER Glow Plug Monitor self-test.

    Is DTC P0670, P0671, P0672, P0673, P0674, P0675, P0676, P0677, P0678, or P0683 present? 

    Yes No
    For DTCs P0671, P0672, P0673, P0674, P0675, P0676, P0677 or P0678, GO to  AF2.
    For DTC P0670, GO to  AF8.
    For DTC P0683, GO to  AF13.    		 Unable to duplicate the condition. CHECK for a loose connection, and damaged or corroded terminals. WIGGLE the harness attempting to recreate the concern. REPAIR as necessary. REFER to NO DTCS PRESENT SYMPTOM CHART INDEX , if a driveability concern exists.
  2. AF2 DIAGNOSTIC TROUBLE CODES (DTCS) P0671, P0672, P0673, P0674, P0675, P0676, P0677, OR P0678 
    NOTE: Refer to the component connector information at the beginning of this pinpoint test.
    NOTE: Glow plugs are numbered front to rear with even numbers on the left side of the engine.
    NOTE: Use the component connector information to match the connector pins with the DTCs.
    • Ignition OFF.
    • Glow Plug Bus Bar connector disconnected.
    • Check for loose, damaged, or backed out terminals.
    • Measure the resistance between:
    (+) Glow Plug Bus Bar Connector, Component Side (-)
    Suspect Glow Plug Ground

    Is the resistance between 0.5 - 2 ohms? 

    Yes No
    GO to  AF4. GO to  AF3.
  3. AF3 CHECK THE GLOW PLUG CIRCUIT BETWEEN THE BUS BAR CONNECTOR AND THE GLOW PLUG 
    • Disconnect the bus bar harness from the glow plugs.
    • Measure the resistance between:
    (+) Glow Plug Bus Bar Connector, Harness Side (-) Glow Plug Connector, Harness Side
    Suspect Glow Plug Suspect Glow Plug

    Is the resistance less than 5 ohms? 

    Yes No
    INSTALL a new glow plug. REFER to the appropriate, Glow Plug System.
    CLEAR the DTCs. REPEAT the self-test.    		 INSTALL a new bus bar.
    CLEAR the DTCs. REPEAT the self-test.
  4. AF4 CHECK THE GLOW PLUG VOLTAGE 
    • Disconnect the suspect GPCM connector.
    • Ignition ON, engine OFF.
    • Measure the voltage between:
    (+) Suspect GPCM Connector, Harness Side (-)
    VBAT Ground

    Is the voltage greater than 10 V? 

    Yes No
    GO to  AF5. REPAIR the open circuit. CLEAR the DTCs.
    REPEAT the self-test.
  5. AF5 CHECK THE GLOW PLUG CIRCUIT FOR AN OPEN 
    • Ignition OFF.
    • Measure the resistance between:
    (+) Suspect GPCM Connector, Harness Side (-) Glow Plug Bus Bar Connector, Harness Side
    Suspect GPCM Suspect Glow Plug

    Is the resistance less than 5 ohms? 

    Yes No
    GO to  AF6. REPAIR the open circuit. CLEAR the DTCs.
    REPEAT the self-test.
  6. AF6 CHECK THE GLOW PLUG CIRCUIT FOR A SHORT TO GROUND 
    • Measure the resistance between:
    (+) Suspect GPCM Connector, Harness Side (-)
    Suspect GPCM Ground

    Is the resistance greater than 10K ohms? 

    Yes No
    GO to  AF7. REPAIR the short circuit. CLEAR the DTCs.
    REPEAT the self-test.
  7. AF7 CHECK THE GLOW PLUG CIRCUIT FOR A SHORT TO VOLTAGE 
    • Ignition ON, engine OFF.
    • Measure the voltage between:
    (+) Suspect GPCM Connector, Harness Side (-)
    Suspect GPCM Ground

    Is any voltage indicated? 

    Yes No
    REPAIR the short circuit. CLEAR the DTCs.
    REPEAT the self-test.    		 INSTALL a new glow plug control module.
    REFER to the appropriate, Glow Plug System.
    CLEAR the DTCs. REPEAT the self-test.
  8. AF8 DIAGNOSTIC TROUBLE CODE (DTC) P0670 
    • Ignition OFF.
    • PCM connector disconnected.
    • GPCM-Green connector disconnected.
    • Measure the resistance between:
    (+) GPCM-Green Connector, Harness Side (-) PCM Connector, Harness Side
    GPE - Pin 8 GPE - Pin E3

    Is the resistance less than 5 ohms? 

    Yes No
    GO to  AF9. REPAIR the open circuit. CLEAR the DTCs.
    REPEAT the self-test.
  9. AF9 CHECK THE CONTROL CIRCUIT FOR A SHORT TO GROUND 
    • Measure the resistance between:
    (+) GPCM-Green Connector, Harness Side (-)
    GPE - Pin 8 Ground

    Is the resistance greater than 10K ohms? 

    Yes No
    GO to  AF10. REPAIR the short circuit. CLEAR the DTCs.
    REPEAT the self-test.
  10. AF10 CHECK THE CONTROL CIRCUIT FOR A SHORT TO VOLTAGE 
    • Ignition ON, engine OFF.
    • Measure the voltage between:
    (+) GPCM-Green Connector, Harness Side (-)
    GPE - Pin 8 Ground

    Is any voltage indicated? 

    Yes No
    REPAIR the short circuit. CLEAR the DTCs.
    REPEAT the self-test.    		 GO to  AF11.
  11. AF11 CHECK THE GLOW PLUG CONTROL MODULE FOR VOLTAGE 
    • Ignition OFF.
    • GPCM-Black connector disconnected.
    • Ignition ON, engine OFF.
    • Measure the voltage between:
    (+) GPCM-Black Connector, Harness Side (-)
    VPWR - Pin 9 Ground

    Is the voltage greater than 10 V? 

    Yes No
    GO to  AF12. REPAIR the open circuit. CLEAR the DTCs.
    REPEAT the self-test.
  12. AF12 CHECK THE GLOW PLUG CONTROL MODULE CONTROL CIRCUIT 
    NOTE: With the ignition ON, engine OFF the PCM provides a path to ground for the glow plug enable (GPE) circuit.
    • Ignition OFF.
    • GPCM-Black connector connected.
    • PCM connector connected.
    • Ignition ON, engine OFF.
    • Measure the voltage between:
    (+) Vehicle Battery (-) GPCM-Green Connector, Harness Side
    Positive terminal GPE - Pin 8

    Is the voltage greater than 10 V? 

    Yes No
    INSTALL a new glow plug control module.
    REFER to the appropriate, Glow Plug System.
    CLEAR the DTCs. REPEAT the self-test.    		 GO to  AF17.
  13. AF13 DIAGNOSTIC TROUBLE CODE (DTC) P0683 
    • Ignition OFF.
    • PCM connector disconnected.
    • GPCM-Green connector disconnected.
    • Measure the resistance between:
    (+) GPCM-Green Connector, Harness Side (-) PCM Connector, Harness Side
    Diagnostic Communication - Pin 9 GPD - Pin E17

    Is the resistance less than 5 ohms? 

    Yes No
    GO to  AF14. REPAIR the open circuit. CLEAR the DTCs.
    REPEAT the self-test.
  14. AF14 CHECK THE DIAGNOSTIC CIRCUIT FOR A SHORT TO GROUND 
    • Measure the resistance between:
    (+) GPCM-Green Connector, Harness Side (-)
    Diagnostic Communication - Pin 9 Ground

    Is the resistance greater than 10K ohms? 

    Yes No
    GO to  AF15. REPAIR the short circuit. CLEAR the DTCs.
    REPEAT the self-test.
  15. AF15 CHECK THE DIAGNOSTIC CIRCUIT FOR A SHORT TO VOLTAGE 
    • Ignition ON, engine OFF.
    • Measure the voltage between:
    (+) GPCM-Green Connector, Harness Side (-)
    Diagnostic Communication - Pin 9 Ground

    Is any voltage indicated? 

    Yes No
    REPAIR the short circuit. CLEAR the DTCs.
    REPEAT the self-test.    		 GO to  AF16.
  16. AF16 CHECK THE GLOW PLUG CONTROL MODULE FOR VOLTAGE 
    • Ignition OFF.
    • GPCM-Black connector disconnected.
    • Ignition ON, engine OFF.
    • Measure the voltage between:
    (+) GPCM-Black Connector, Harness Side (-)
    VPWR - Pin 9 Ground

    Is the voltage greater than 10 V? 

    Yes No
    INSTALL a new glow plug control module.
    REFER to the appropriate, Glow Plug System.
    CLEAR the DTCs. REPEAT the self-test.    		 REPAIR the open circuit. CLEAR the DTCs.
    REPEAT the self-test.
  17. AF17 CHECK FOR CORRECT PCM OPERATION 
    • Disconnect all the PCM connectors.
    • Visually inspect for:
      • pushed out pins
      • corrosion
    • Connect all the PCM connectors and make sure they seat correctly.
    • Carry out the PCM self-test and verify the concern is still present.

    Is the concern still present? 

    Yes No
    INSTALL a new PCM. REFER to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) , Programming the VID Block for a Replacement PCM. The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.
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