LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Nissan-Datsun >> 2021 >> Sentra SR >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System (2 Of 2) >> Components/Circuit Diagnosis >> Fuel Injector >> Diagnosis Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnosis Procedure

  1. CHECK FUSE 
    1. Turn ignition switch OFF.
    2. Check that the following fuse is not blowing.

      Fuse No.

      Capacity

      No. 60

      10 A

      No. 64

      15 A

    Is the fuse blown (open)?

    YES

    Replace the fuse after repairing the applicable circuit.

    NO

    GO TO 2.

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

      +

      -

      Voltage

      ECM

      Connector

      Terminal

      F24

      3

      Ground

      Battery voltage

      4

    Is the inspection result normal?

    YES

    GO TO 9.

    NO

    GO TO 3.

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

      ECM

      Direct fuel injector relay 1 and 2

      Continuity

      Connector

      Terminal

      Connector

      Terminal

      F24

      3

      F60

      2

      Existed

      4

      7
    5. Also check harness for short to ground and short to power.

    Is the inspection result normal?

    YES

    GO TO 4.

    NO

    Repair or replace malfunctioning part.

  4. CHECK DIRECT FUEL INJECTOR RELAY 1 AND 2 POWER SUPPLY (CONTACT SIDE) 

    Check the voltage between fuel injector relay harness connector and ground.

    +

    -

    Voltage

    Direct fuel injector relay 1 and 2

    Connector

    Terminal

    F60

    1

    Ground

    Battery voltage

    6

    Is the inspection result normal?

    YES

    GO TO 5.

    NO

    Perform trouble diagnosis for power supply circuit.

  5. CHECK DIRECT FUEL INJECTOR RELAY 1 AND 2 POWER SUPPLY (EXCITATION COIL SIDE) 
    1. Install all removed parts.
    2. Turn ignition switch ON.
    3. Check the voltage between direct fuel injector relay 1 and 2 harness connector and ground.

      +

      -

      Voltage

      Direct fuel injector relay 1 and 2

      Connector

      Terminal

      F60

      3

      Ground

      Battery voltage

      8

    Is the inspection result normal?

    YES

    GO TO 7.

    NO

    GO TO 6.

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

      IPDM E/R

      Direct fuel injector relay 1 and 2

      Continuity

      Connector

      Terminal

      Connector

      Terminal

      F96

      73

      F60

      3

      Existed

      8
    5. Also check harness for short to ground and short to power.

    Is the inspection result normal?

    YES

    Perform trouble diagnosis for power supply circuit.

    NO

    Repair or replace malfunctioning part.

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

      Direct fuel injector relay 1 and 2

      --

      Continuity

      Connector

      Terminal

      F60

      4

      Ground

      Existed

      9
    4. Also check harness for short to power.

    Is the inspection result normal?

    YES

    GO TO 8.

    NO

    Repair or replace malfunctioning part.

  8. CHECK DIRECT FUEL INJECTOR RELAY 1 AND 2 

    Refer to Component Inspection .

    Is the inspection result normal?

    YES

    Check intermittent incident. Refer to Intermittent Incident .

    NO

    Replace direct fuel injector relay 1 and 2.

  9. CHECK ECM GROUND CIRCUIT 
    1. Turn ignition switch OFF.
    2. Check the continuity between ECM harness connector and ground.

      ECM

      --

      Continuity

      Connector

      Terminal

      F24

      5

      Ground

      Existed

      65

      F25

      69

      E16

      157

      159

      162
    3. Also check harness for short to power.

    Is the inspection result normal?

    YES

    GO TO 10.

    NO

    Repair or replace malfunctioning part.

  10. 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

      F18

      2

      F24

      8

      Existed

      2

      F19

      2

      7

      3

      F20

      2

      9

      4

      F21

      2

      6
    4. Also check harness for short to ground.

    Is the inspection result normal?

    YES

    GO TO 11.

    NO

    Repair or replace malfunctioning part.

  11. CHECK FUEL INJECTOR 

    Refer to Component Inspection .

    Is the inspection result normal?

    YES

    Check intermittent incident. Refer to Intermittent Incident .

    NO

    Replace malfunctioning fuel injector. Refer to Removal and Installation .

scientia non olet · About LEMON Manuals