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Home >> Nissan-Datsun >> 2004 >> Pathfinder LE, 4WD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System >> Basic Service Procedure >> Idle Speed/Ignition Timing/Idle Mixture Ratio Adjustment >> Inspection Procedure
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Inspection Procedure

  1. INSPECTION START 
    1. Check service records for any recent repairs that may indicate a related malfunction, or a current need for scheduled maintenance.
    2. Open engine hood and check the following:
      • Harness connectors for improper connections
      • Wiring harness for improper connections, pinches and cut
      • Vacuum hoses for splits, kinks and improper connections
      • Hoses and ducts for leaks
      • Air cleaner clogging
      • Gasket
        Fig 1: Identifying Wiring Harness Pinches And Cut
        G00334242Courtesy of NISSAN MOTOR CO., U.S.A.
    3. Confirm that electrical or mechanical loads are not applied.
      • Headlamp switch is OFF.
      • Air conditioner switch is OFF.
      • Rear window defogger switch is OFF.
      • Steering wheel is in the straight-ahead position, etc.
    4. Start engine and warm it up until engine coolant temperature indicator points the middle of gauge.

      Ensure engine stays below 1,000 RPM.

      Fig 2: Identifying Engine Coolant Temperature Indicator Points Middle Of Gauge
      G00334243Courtesy of NISSAN MOTOR CO., U.S.A.
    5. Run engine at about 2,000 RPM for about 2 minutes under no-load.
      Fig 3: Identifying Run Engine At About 2,000 RPM 2 Minutes Under No-Load
      G00334244Courtesy of NISSAN MOTOR CO., U.S.A.
    6. Make sure that no DTC is displayed with CONSULT-II or GST.

    OK or NG 

    1. OK GO TO  3 .
    2. NG GO TO 2.
  2. REPAIR OR REPLACE 

    Repair or replace components as necessary according to corresponding Diagnostic Procedure.

    1. GO TO 3.
  3. CHECK TARGET IDLE SPEED 

    With CONSULT-II 

    1. Run engine at about 2,000 RPM for about 2 minutes under no-load.
    2. Rev engine (2,000 to 3,000 RPM) two or three times under no-load, then run engine at idle speed for about 1 minute.
      Fig 4: Identifying Rev Engine (2,000 To 3,000 RPM) Two Or Three Times Under No-Load
      G00334245Courtesy of NISSAN MOTOR CO., U.S.A.
    3. Read idle speed in "DATA MONITOR" mode with CONSULT-II.
      Fig 5: Displaying Data Monitor
      G00334246Courtesy of NISSAN MOTOR CO., U.S.A.

      M/T: 750+/-50 RPM 

      A/T: 750+/-50 RPM (in P or N position) 

    Without CONSULT-II 

    1. Run engine at about 2,000 RPM for about 2 minutes under no-load.
    2. Rev engine (2,000 to 3,000 RPM) two or three times under no-load, then run engine at idle speed for about 1 minute.
    3. Check idle speed.

      M/T: 750+/-50 RPM 

      A/T: 750+/-50 RPM (in P or N position) 

    OK or NG 

    1. OK GO TO  10 .
    2. NG GO TO 4.
  4. PERFORM  ACCELERATOR PEDAL RELEASED POSITION LEARNING  
    1. Stop engine.
    2. Perform "ACCELERATOR PEDAL RELEASED POSITION LEARNING  " .
    1. GO TO 5.
  5. PERFORM  THROTTLE VALVE CLOSED POSITION LEARNING  

    Perform "THROTTLE VALVE CLOSED POSITION LEARNING  " .

    1. GO TO 6.
  6. PERFORM  IDLE AIR VOLUME LEARNING  

    Perform "IDLE AIR VOLUME LEARNING  " .

    Is Idle Air Volume Learning carried out successfully? 

    Yes or No 

    1. Yes GO TO 7.
    2. No
    1. Follow the instruction of Idle Air Volume Learning.
    2. GO TO  4 .
  7. CHECK TARGET IDLE SPEED AGAIN 

    With CONSULT-II 

    1. Start engine and warm it up to normal operating temperature.
    2. Read idle speed in "DATA MONITOR" mode with CONSULT-II.

      M/T: 750+/-50 RPM 

      A/T: 750+/-50 RPM (in P or N position) 

    Without CONSULT-II 

    1. Start engine and warm it up to normal operating temperature.
    2. Check idle speed.

      M/T: 750+/-50 RPM 

      A/T: 750+/-50 RPM (in P or N position) 

    OK or NG 

    1. OK GO TO  10 .
    2. NG GO TO 8.
  8. DETECT MALFUNCTIONING PART 

    Check the following.

    OK or NG 

    1. OK GO TO 9.
    2. NG
      1. Repair or replace.
      2. GO TO  4 .
  9. CHECK ECM FUNCTION 
    1. Substitute another known-good ECM to check ECM function. (ECM may be the cause of an incident, but this is a rare case.)
    2. Perform initialization of NVIS (NATS) system and registration of NVIS (NATS) ignition key IDs. Refer to "NVIS (NISSAN VEHICLE IMMOBILIZER SYSTEM - NATS)  " .
    1. GO TO  4 .
  10. CHECK IGNITION TIMING 
    1. Run engine at idle.
    2. Check ignition timing with a timing light.
      Fig 6: Checking Ignition Timing
      G00334247Courtesy of NISSAN MOTOR CO., U.S.A.

      M/T: 15°+/-5° BTDC 

      A/T: 15°+/-5° BTDC (in P or N position) 

    OK or NG 

    1. OK (With CONSULT-II) GO TO  19 .
    2. OK (Without CONSULT-II) GO TO  20 .
    3. NG GO TO 11.
  11. PERFORM  ACCELERATOR PEDAL RELEASED POSITION LEARNING  
    1. Stop engine.
    2. Perform "ACCELERATOR PEDAL RELEASED POSITION LEARNING  " .
    1. GO TO 12.
  12. PERFORM  THROTTLE VALVE CLOSED POSITION LEARNING  

    Perform "THROTTLE VALVE CLOSED POSITION LEARNING  " .

    1. GO TO 13.
  13. PERFORM  IDLE AIR VOLUME LEARNING  

    Perform "IDLE AIR VOLUME LEARNING  " .

    Is Idle Air Volume Learning carried out successfully? 

    Yes or No 

    1. Yes GO TO 14.
    2. No
      1. Follow the instruction of Idle Air Volume Learning.
      2. GO TO  4 .
  14. CHECK TARGET IDLE SPEED AGAIN 

    With CONSULT-II 

    1. Start engine and warm it up to normal operating temperature.
    2. Read idle speed in "DATA MONITOR" mode with CONSULT-II.

      M/T: 750+/-50 RPM 

      A/T: 750+/-50 RPM (in P or N position) 

    Without CONSULT-II 

    1. Start engine and warm it up to normal operating temperature.
    2. Check idle speed.

      M/T: 750+/-50 RPM 

      A/T: 750+/-50 RPM (in P or N position) 

    OK or NG 

    1. OK GO TO 15.
    2. NG GO TO  17 .
  15. CHECK IGNITION TIMING AGAIN 
    1. Run engine at idle.
    2. Check ignition timing with a timing light.
      Fig 7: Checking Ignition Timing
      G00334248Courtesy of NISSAN MOTOR CO., U.S.A.

      M/T: 15°+/-5° BTDC 

      A/T: 15°+/-5° BTDC (in P or N position) 

    OK or NG 

    1. OK (With CONSULT-II) GO TO  19 .
    2. OK (Without CONSULT-II) GO TO  20 .
    3. NG GO TO 16.
  16. CHECK TIMING CHAIN INSTALLATION 

    Check timing chain installation. Refer to "TIMING CHAIN ".

    OK or NG 

    1. OK GO TO 17.
    2. NG
      1. Repair the timing chain installation.
      2. GO TO  4 .
  17. DETECT MALFUNCTIONING PART 

    Check the following.

    OK or NG 

    1. OK GO TO 18.
    2. NG
      1. Repair or replace.
      2. GO TO  4 .
  18. CHECK ECM FUNCTION 
    1. Substitute another known-good ECM to check ECM function. (ECM may be the cause of an incident, but this is a rare case.)
    2. Perform initialization of NVIS (NATS) system and registration of NVIS (NATS) ignition key IDs. Refer to "NVIS (NISSAN VEHICLE IMMOBILIZER SYSTEM - NATS)  " .
    1. GO TO  4 .
  19. CHECK HEATED OXYGEN SENSOR 1 (BANK 1) SIGNAL 

    With CONSULT-II 

    1. Run engine at about 2,000 RPM for about 2 minutes under no-load.
    2. See "HO2S1 MNTR (B1)" in "DATA MONITOR" mode.
    3. Running engine at 2,000 RPM under no-load (The engine is warmed up to normal operating temperature.), check that the monitor fluctuates between LEAN and RICH more than 5 times during 10 seconds.
      Fig 8: Displaying Lean And Rich
      G00334249Courtesy of NISSAN MOTOR CO., U.S.A.

      1 time: RICH --> LEAN --> RICH 

      2 times: RICH --> LEAN --> RICH --> LEAN --> RICH 

    OK or NG 

    1. OK GO TO  21 .
    2. NG (Monitor does not fluctuate.) GO TO  23 .
    3. NG (Monitor fluctuates less than 5 times.) GO TO  31 .
  20. CHECK HEATED OXYGEN SENSOR 1 (BANK 1) SIGNAL 

    Without CONSULT-II 

    1. Stop engine and set ECM to Self-diagnostic mode II (Heated oxygen sensor 1 monitor). Refer to "HOW TO SWITCH DIAGNOSTIC TEST MODE  " .
    2. Start engine and run it at about 2,000 RPM for about 2 minutes under no-load.
    3. Running engine at 2,000 RPM under no-load (The engine is warmed up to normal operating temperature.), check that the MIL comes on more than 5 times during 10 seconds.

    OK or NG 

    1. OK GO TO  22 .
    2. NG (MIL does not come on) GO TO  23 .
    3. NG (MIL comes on less than 5 times) GO TO  31 .
  21. CHECK HEATED OXYGEN SENSOR 1 (BANK 2) SIGNAL 

    With CONSULT-II 

    1. See "HO2S1 MNTR (B2)" in "DATA MONITOR" mode.
    2. Running engine at 2,000 RPM under no-load (The engine is warmed up to normal operating temperature.), check that the monitor fluctuates between LEAN and RICH more than 5 times during 10 seconds.
      Fig 9: Displaying Data Monitor
      G00334250Courtesy of NISSAN MOTOR CO., U.S.A.

      1 time: RICH --> LEAN --> RICH 

      2 times: RICH --> LEAN --> RICH --> LEAN --> RICH 

    OK or NG 

    1. OK INSPECTION END 
    2. NG (Monitor does not fluctuate.) GO TO  24 .
    3. NG (Monitor fluctuates less than 5 times.) GO TO  31 .
  22. CHECK HEATED OXYGEN SENSOR 1 (BANK 2) SIGNAL 

    Without CONSULT-II 

    1. Switch the monitored sensor from bank 1 to bank 2. Refer to "HOW TO SET DIAGNOSTIC SWITCH MONITORED SENSOR FROM BANK 1 TO BANK 2 OR VICE VERSA  " .
    2. Running engine at 2,000 RPM under no-load (The engine is warmed up to normal operating temperature.), check that the MIL comes on more than 5 times during 10 seconds.

    OK or NG 

    1. OK INSPECTION END 
    2. NG (MIL does not come on) GO TO  24 .
    3. NG (MIL comes on less than 5 times) GO TO  31 .
  23. CHECK HEATED OXYGEN SENSOR 1 (BANK 1) HARNESS 
    1. Turn ignition switch OFF and disconnect battery ground cable.
    2. Disconnect ECM harness connector.
    3. Disconnect heated oxygen sensor 1 (bank 1) harness connector.
    4. Check harness continuity between ECM terminal 35 and heated oxygen sensor 1 (bank 1) terminal 1. Refer to "WIRING DIAGRAM  " .

      Continuity should exist. 

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

    OK or NG 

    1. OK GO TO  25 .
    2. NG
      1. Repair or replace harness between ECM and heated oxygen sensor 1 (bank 1).
      2. GO TO  4 .
  24. CHECK HEATED OXYGEN SENSOR 1 (BANK 2) HARNESS 
    1. Turn ignition switch OFF and disconnect battery ground cable.
    2. Disconnect ECM harness connector.
    3. Disconnect heated oxygen sensor 1 (bank 2) harness connector.
    4. Check harness continuity between ECM terminal 16 and heated oxygen sensor 1 (bank 2) terminal 1. Refer to "WIRING DIAGRAM  " .

      Continuity should exist. 

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

    OK or NG 

    1. OK GO TO 25.
    2. NG
      1. Repair or replace harness between ECM and heated oxygen sensor 1 (bank 2).
      2. GO TO  4 .
  25. PERFORM ACCELERATOR PEDAL RELEASED POSITION LEARNING 
    1. Reconnect ECM harness connector.
    2. Perform "ACCELERATOR PEDAL RELEASED POSITION LEARNING  " .
    1. GO TO 26.
  26. PERFORM  THROTTLE VALVE CLOSED POSITION LEARNING  

    Perform "THROTTLE VALVE CLOSED POSITION LEARNING  " .

    1. GO TO 27.
  27. PERFORM  IDLE AIR VOLUME LEARNING  

    Perform "IDLE AIR VOLUME LEARNING  " .

    Is Idle Air Volume Learning carried out successfully? 

    Yes or No 

    1. Yes (With CONSULT-II) GO TO 28.
    2. Yes (Without CONSULT-II) GO TO  29 .
    3. No
      1. Follow the instruction of Idle Air Volume Learning.
      2. GO TO  4 .
  28. CHECK CO % 

    With CONSULT-II 

    1. Start engine and warm it up until engine coolant temperature indicator points to the middle of gauge.
    2. Turn ignition switch OFF, wait at least 10 seconds and then turn ON.
    3. Select "ENG COOLANT TEMP" in "ACTIVE TEST" mode.
    4. Set "ENG COOLANT TEMP" to 5°C (41°F) by touching "DWN" and "Qd".
    5. Start engine and rev it (2,000 to 3,000 RPM) two or three times under no-load, then run engine at idle speed.
    6. Check Co %.
      Fig 10: Displaying ENG Coolant Temp In Data Monitor
      G00334251Courtesy of NISSAN MOTOR CO., U.S.A.

      Idle CO: 0.7 - 9.9% and engine runs smoothly. 

    OK or NG 

    1. OK GO TO  31 .
    2. NG GO TO 30.
  29. CHECK CO % 

    Without CONSULT-II 

    1. Start engine and warm it up until engine coolant temperature indicator points to the middle of gauge.
    2. Turn ignition switch OFF.
    3. Disconnect engine coolant temperature sensor harness connector.
    4. Connect a resistor (4.4 kohm) between terminals of engine coolant temperature sensor harness connector.
    5. Start engine and rev it (2,000 to 3,000 RPM) two or three times under no-load, then run engine at idle speed.
    6. Check CO %.

      Idle CO: 0.7 - 9.9% and engine runs smoothly. 

    7. After checking CO %, turn ignition switch OFF, disconnect the resistor from the terminals of engine coolant temperature sensor harness connector, and then connect engine coolant temperature sensor harness connector to engine coolant temperature sensor.
      Fig 11: Disconnecting Resistor From Terminals Of Engine Coolant Temperature Sensor Harness Connector
      G00334252Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK GO TO  31 .
    2. NG GO TO 30.
  30. RECONNECT HEATED OXYGEN SENSOR 1 HARNESS CONNECTOR 
    1. Turn ignition switch OFF.
    2. Reconnect heated oxygen sensor 1 harness connector.
    1. GO TO  34 .
  31. REPLACE HEATED OXYGEN SENSOR 1 
    1. Stop engine.
    2. Replace heated oxygen sensor 1 on the malfunctioning bank.
    1. With CONSULT-II GO TO 32.
    2. Without CONSULT-II GO TO  33 .
  32. CHECK HEATED OXYGEN SENSOR 1 (BANK 1)/(BANK 2) SIGNAL 

    With CONSULT-II 

    1. Start engine and warm it up until engine coolant temperature indicator points to the middle of gauge.
    2. See "HO2S1 MNTR (B1)/(B2)" in "DATA MONITOR" mode.
    3. Running engine at 2,000 RPM under no-load (The engine is warmed up to normal operating temperature.), check that the monitor fluctuates between LEAN and RICH more than 5 times during 10 seconds.

      1 time: RICH --> LEAN --> RICH 

      2 times: RICH --> LEAN --> RICH --> LEAN --> RICH 

    OK or NG 

    1. OK GO TO  4 .
    2. NG GO TO  34 .
  33. CHECK HEATED OXYGEN SENSOR 1 (BANK 1)/(BANK 2) SIGNAL 

    Without CONSULT-II 

    1. Set ECM to Self-diagnostic mode II (Heated oxygen sensor 1 monitor). Refer to "HOW TO SWITCH DIAGNOSTIC TEST MODE  " .
    2. Switch the monitored sensor to the malfunctioning bank. Refer to "HOW TO SET DIAGNOSTIC SWITCH MONITORED SENSOR FROM BANK 1 TO BANK 2 OR VICE VERSA  " .
    3. Running engine at 2,000 RPM under no-load (The engine is warmed up to normal operating temperature.), check that the MIL comes on more than 5 times during 10 seconds.

    OK or NG 

    1. OK GO TO  4 .
    2. NG GO TO 34.
  34. DETECT MALFUNCTIONING PART 

    Check the following.

    OK or NG 

    1. OK GO TO 36.
    2. NG
      1. Repair or replace.
      2. GO TO 35.
  35. ERASE UNNECESSARY DTC 

    After this inspection, unnecessary DTC might be displayed.

    Erase the stored memory in ECM and TCM. Refer to "HOW TO ERASE EMISSION-RELATED DIAGNOSTIC INFORMATION  " .

    1. GO TO  4 .
  36. CHECK ECM FUNCTION 
    1. Substitute another known-good ECM to check ECM function. (ECM may be the cause of an incident, but this is a rare case.)
    2. Perform initialization of NVIS (NATS) system and registration of NVIS (NATS) ignition key IDs. Refer to "NVIS (NISSAN VEHICLE IMMOBILIZER SYSTEM - NATS)  " .
    1. GO TO  4 .