2012 Infiniti G25 BaseFACTORY OEM SERVICE PROCEDURE

Diagnosis Procedure

  1. CHECK IGNITION COIL POWER SUPPLY CIRCUIT-I
    1. Turn ignition switch OFF, wait at least 10 seconds and then turn ON.
    2. Check the voltage between ECM harness connector terminals under the following conditions.
      ECM Voltage
      Connector + -
      Terminal Terminal
      M107 125 128 Battery voltage

      Is the inspection result normal? 

      YES: GO TO 2.

      NO: Go to "DIAGNOSIS PROCEDURE ".

  2. CHECK IGNITION COIL POWER SUPPLY CIRCUIT-II
    1. Turn ignition switch OFF.
    2. Disconnect condenser harness connector.
    3. Turn ignition switch ON.
    4. Check the voltage between condenser harness connector and ground.
      Condenser Ground Voltage
      Connector Terminal
      F8 1 Ground Battery voltage

      Is the inspection result normal? 

      YES: GO TO  5.

      NO: GO TO 3.

  3. CHECK IGNITION COIL POWER SUPPLY CIRCUIT-III
    1. Turn ignition switch OFF.
    2. Disconnect IPDM E/R harness connector.
    3. Check the continuity between IPDM E/R harness connector and condenser harness connector.
      IPDM E/R Condenser Continuity
      Connector Terminal Connector Terminal
      E7 53 F8 1 Existed
    4. Also check harness for short to ground and short to power.

      Is the inspection result normal? 

      YES: Go to "DIAGNOSIS PROCEDURE ".

      NO: GO TO 4.

  4. DETECT MALFUNCTIONING PART

    Check the following.

    • Harness connectors E25, F30
    • Harness for open or short between IPDM E/R and condenser

      Repair open circuit or short to ground or short to power in harness or connectors.

  5. CHECK CONDENSER GROUND CIRCUIT FOR OPEN AND SHORT
    1. Turn ignition switch OFF.
    2. Check the continuity between condenser harness connector and ground.
      Condenser Ground Continuity
      Connector Terminal
      F8 2 Ground Existed
    3. Also check harness for short to power.

      Is the inspection result normal? 

      YES: GO TO 6.

      NO: Repair open circuit or short to power in harness or connectors.

  6. CHECK CONDENSER

    Refer to "COMPONENT INSPECTION (CONDENSER) "

    Is the inspection result normal? 

    YES: GO TO 7.

    NO: Replace condenser.

  7. CHECK IGNITION COIL POWER SUPPLY CIRCUIT-IV
    1. Reconnect all harness connectors disconnected.
    2. Disconnect ignition coil harness connector.
    3. Turn ignition switch ON.
    4. Check the voltage between ignition coil harness connector and ground.
      Ignition coil Ground Voltage
      Cylinder Connector Terminal
      1 F11 3 Ground Battery voltage
      2 F12 3
      3 F13 3
      4 F14 3
      5 F15 3
      6 F16 3

      Is the inspection result normal? 

      YES: GO TO  9.

      NO: GO TO 8.

  8. DETECT MALFUNCTIONING PART

    Check the following.

    • Harness connector E25, F30
    • Harness for open or short between ignition coil and harness connector F30

      Repair or replace harness or connectors.

  9. CHECK IGNITION COIL GROUND CIRCUIT FOR OPEN AND SHORT
    1. Turn ignition switch OFF.
    2. Check the continuity between ignition coil harness connector and ground.
      Ignition coil Ground Continuity
      Cylinder Connector Terminal
      1 F11 2 Ground Existed
      2 F12 2
      3 F13 2
      4 F14 2
      5 F15 2
      6 F16 2
    3. Also check harness for short to power.

      Is the inspection result normal? 

      YES: GO TO 10.

      NO: Repair open circuit or short to power in harness or connectors.

  10. CHECK IGNITION COIL OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
    1. Disconnect ECM harness connector.
    2. Check the continuity between ignition coil harness connector and ECM harness connector.
      Ignition coil ECM Continuity
      Cylinder Connector Terminal Connector Terminal
      1 F11 1 F101 20 Existed
      2 F12 1 16
      3 F13 1 12
      4 F14 1 11
      5 F15 1 15
      6 F16 1 19
    3. Also check harness for short to ground and short to power.

      Is the inspection result normal? 

      YES: GO TO  12.

      NO: GO TO 11.

  11. DETECT MALFUNCTIONING PART

    Check the following.

    • Harness connector F104, F105
    • Harness for open or short between ignition coil and ECM

      Repair or replace harness or connectors.

  12. CHECK IGNITION COIL WITH POWER TRANSISTOR

    Refer to "COMPONENT INSPECTION (IGNITION COIL WITH POWER TRANSISTOR) ".

    Is the inspection result normal? 

    YES: GO TO 13.

    NO: Replace malfunctioning ignition coil with power transistor. Refer to "REMOVAL AND INSTALLATION ".

  13. CHECK INTERMITTENT INCIDENT

    Refer to "INTERMITTENT INCIDENT ".

    INSPECTION END

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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