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Home >> Infiniti >> 2022 >> QX80 Premium Select, AWD >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System (Diagnostics) (1 Of 2) >> Component/Circuit Diagnosis >> Fuel Injector >> Diagnosis Procedure

Diagnosis Procedure

  1. CHECK FUEL INJECTOR POWER SUPPLY CIRCUIT 
    1. Turn ignition switch OFF.
    2. Disconnect fuel injector harness connector.
    3. Turn ignition switch ON.
    4. Check the voltage between fuel injector harness connector and ground.

      +

      -

      Voltage

      Fuel injector

      Cylinder

      Connector

      Terminal

      1

      F123

      1

      Ground

      Battery voltage

      2

      F124

      1

      3

      F125

      1

      4

      F126

      1

      5

      F127

      1

      6

      F128

      1

      7

      F129

      1

      8

      F130

      1

    Is the inspection result normal?

    YES

    GO TO 9.

    NO

    GO TO 2.

  2. CHECK FUEL INJECTOR POWER SUPPLY CIRCUIT 
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check the continuity between fuel injector harness connector and ECM harness connector.

      Fuel injector

      ECM

      Continuity

      Cylinder

      Connector

      Terminal

      Connector

      Terminal

      1

      F123

      1

      F91

      47

      Existed

      2

      F124

      1

      5

      3

      F125

      1

      4

      F126

      1

      54

      5

      F127

      1

      7

      6

      F128

      1

      47

      7

      F129

      1

      54

      8

      F130

      1

      7

    4. Also check harness for short to ground.

    Is the inspection result normal?

    YES

    GO TO 3.

    NO

    Repair or replace error-detected parts.

  3. CHECK FUEL INJECTOR DRIVER POWER SUPPLY 
    1. Reconnect ECM harness connector.
    2. Turn ignition switch ON.
    3. Check the voltage between ECM harness connector and ground.

      +

      -

      Voltage

      ECM

      Connector

      Terminal

      F91

      1

      Ground

      Battery voltage

      2

      6

      46

    Is the inspection result normal?

    YES

    Check intermittent incident. Refer to Inspection .

    NO

    GO TO 4.

  4. CHECK FUEL INJECTOR DRIVER POWER SUPPLY CIRCUIT 
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Disconnect fuel injector relay harness connector.
    4. Check the continuity between ECM harness connector and fuel injector relay harness connector.

      ECM

      Fuel injector relay

      Continuity

      Connector

      Terminal

      Connector

      Terminal

      F91

      1

      E26

      3

      Existed

      2

      6

      6

      3

      46

      6

    5. Also check harness for short to ground.

    Is the inspection result normal?

    YES

    GO TO 5.

    NO

    Repair or replace error-detected parts

  5. CHECK FUEL INJECTOR RELAY POWER SUPPLY (CONTACT SIDE) 
    1. Turn ignition switch ON.
    2. Check the voltage between fuel injector relay harness connector and ground.

    +

    -

    Voltage

    Fuel injector relay

    Connector

    Terminal

    E26

    5

    Ground

    Battery voltage

    7

    Is the inspection result normal?

    YES

    GO TO 6.

    NO

    Perform the trouble diagnosis for power supply circuit.

  6. CHECK FUEL INJECTOR RELAY POWER SUPPLY (EXCITATION COIL SIDE) 
    1. Reconnect all harness connectors disconnected.
    2. Check the voltage between fuel injector relay harness connector and ground.

      +

      -

      Voltage

      Fuel injector relay

      Connector

      Terminal

      E26

      2

      Ground

      Battery voltage

    Is the inspection result normal?

    YES

    GO TO 8.

    NO

    GO TO 7.

  7. CHECK FUEL INJECTOR RELAY POWER SUPPLY CIRCUIT (EXCITATION COIL SIDE) 
    1. Turn ignition switch OFF.
    2. Disconnect fuel injector relay harness connector.
    3. Disconnect IPDM E/R harness connector.
    4. Check the continuity between IPDM E/R harness connector and fuel injector harness connector.

      IPDM E/R

      Fuel injector relay

      Continuity

      Connector

      Terminal

      Connector

      Terminal

      E14

      36

      E26

      2

      Existed

    5. Also check harness for short to ground.

    Is the inspection result normal?

    YES

    Perform the trouble diagnosis for power supply circuit.

    NO

    Repair or replace error-detected parts.

  8. CHECK FUEL INJECTOR RELAY GROUND CIRCUIT 
    1. Turn ignition switch OFF.
    2. Disconnect fuel injector relay harness connector.
    3. Check the continuity between fuel injector relay harness connector and ground.

      Fuel injector relay

      -

      Continuity

      Connector

      Terminal

      E26

      1

      Ground

      Existed

    4. Also check harness for short to power.

    Is the inspection result normal?

    YES

    GO TO 10.

    NO

    Repair or replace error-detected parts.

  9. CHECK FUEL INJECTOR GROUND CIRCUIT 
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check the continuity between fuel injector harness connector and ECM harness connector.

      Fuel injector

      ECM

      Continuity

      Cylinder

      Connector

      Terminal

      Connector

      Terminal

      1

      F123

      2

      F91

      48

      Existed

      2

      F124

      2

      9

      3

      F125

      2

      4

      4

      F126

      2

      49

      5

      F127

      2

      8

      6

      F128

      2

      52

      7

      F129

      2

      53

      8

      F130

      2

      3

    4. Also check harness for short to ground and to power.

    Is the inspection result normal?

    YES

    GO TO 11.

    NO

    Repair or replace error-detected parts.

  10. CHECK FUEL INJECTOR RELAY 

    Check the fuel injector relay. Refer to Component Inspection .

    Is the inspection result normal?

    YES

    Check intermittent incident. Refer to Inspection .

    NO

    Replace fuel injector relay.

  11. CHECK FUEL INJECTOR 

    Check the fuel injector. Refer to Component Inspection .

    Is the inspection result normal?

    YES

    Check intermittent incident. Refer to Inspection .

    NO

    Replace malfunctioning fuel injector. Refer to FUEL INJECTOR AND FUEL TUBE : Exploded View .