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Home >> Infiniti >> 2003 >> M45 >> Repair and Diagnosis >> Engine Performance >> Engine Controls - On-Vehicle Adjustments >> Throttle Position Sensor, Ignition Timing & Idle Speed >> Basic Inspection >> I35

Basic Inspection: I35

  1. Check service records for any recent repairs that may indicate a related problem, or a current need for a scheduled maintenance.
  2. Check the following:
    • Harness connectors for improper connections.
    • Wiring harness for improper connections, pinches and cuts.
    • Vacuum hoses for splits, kinks and improper connections.
    • Hoses and ducts for leaks.
    • Air cleaner clogging.
    • Gasket.
    • Confirm that electrical or mechanical loads are not applied.
    • Ensure headlights, A/C and rear window defogger are turned off.
    • Ensure steering wheel is in straight-ahead position.
    Start engine and warm it up until engine coolant temperature gauge is pointing to the middle of gauge. Ensure engine stays below 1000 RPM. Hold engine speed at 2000 RPM for about 2 minutes. Using scan tool, ensure no DTCs are set. If problem is found, repair as necessary. If problem is not found, go to next step.
  3. Run engine at about 2000 RPM for about 2 minutes under no load. Quickly increase engine speed to 2000-3000 RPM 2 or 3 times. Let engine idle for about one minute. Check idle speed. Idle should be 600-700 RPM with transmission in Park or Neutral. If idle speed is as specified, go to step  10. If idle speed is not as specified, go to next step.
  4. Turn engine off. Perform Accelerator Pedal Released Position Learning procedure. See appropriate SELF DIAGNOSTICS article. If procedure okay, go to next step.
  5. Perform the Throttle Valve Closed Position Learning procedure. See appropriate SELF DIAGNOSTICS article. If procedure is okay, go to next step.
  6. Perform the Idle Air Volume Learning procedure. See appropriate SELF DIAGNOSTICS article. If procedure okay, go to next step. If result is incomplete, repair as necessary, then go to step  4.
  7. Start engine and warm to normal operating temperature. Check target idle speed. Idle speed should be 625-725 RPM with transmission in Park or Neutral. If idle speed is as specified, go to step  10. If idle speed is not as specified, go to next step.
  8. Check the following:
    • Camshaft position sensor (PHASE) and circuit. See appropriate SELF-DIAGNOSTICS article.
    • Crankshaft position sensor (POS) and circuit. See appropriate SELF-DIAGNOSTICS article.
    If okay, go to next step. If not, repair or replace as necessary. Go to step  4.
  9. Substitute another known-good ECM to check ECM functionality. Go to step  4.
  10. Check ignition timing at idle with a timing light. Ignition timing should be 10-20 degrees BTDC in Park or Neutral. If ignition timing is as specified, then go to step  19. If ignition timing is not as specified, go to next step.
  11. Perform Accelerator Pedal Released position learning. See appropriate SELF DIAGNOSTICS article. If procedure okay, go to next step.
  12. Perform the Throttle Valve Closed Position Learning procedure. See appropriate SELF DIAGNOSTICS article. If procedure okay, go to next step.
  13. Perform Idle Air Volume Learning procedure. See appropriate SELF DIAGNOSTICS article. If procedure okay, go to next step. If result is incomplete, repair as necessary, then go to next step.
  14. Start engine and warm to normal operating temperature. Check target idle speed again. Idle speed should be 625-725 RPM with transmission in Park or Neutral. If idle speed is okay, go to next step. If idle speed is not okay, go to step  17.
  15. Check ignition timing again at idle with a timing light. Ignition timing should be 10-20 degrees BTDC in Park or Neutral. If ignition timing is okay, go to step  19. If ignition timing is not okay go to next step.
  16. Check timing chain installation. See appropriate ENGINE article. If timing chain installation is okay, go to next step. If timing chain installation is not okay, repair as necessary, then go to step  4.
  17. Check the following:
    • Camshaft position sensor (PHASE) and circuit. See appropriate SELF-DIAGNOSTICS article.
    • Crankshaft position sensor (POS) and circuit. See appropriate SELF-DIAGNOSTICS article.
    • If okay, go to next step. If not, repair or replace as necessary. Go to step  4.
  18. Substitute another known-good ECM to check ECM functionality. Go to step  4.
  19. Check Heated Oxygen Sensor 1 (Bank 1) signal. Run engine at normal operating temperature to 2000 RPM for about 2 minutes under no-load. If testing is as specified, go to step  20. If testing is not as specified, proceed accordingly:
    • With CONSULT II -  Check that the monitor fluctuates between Lean and Rich more than 5 times during 10 seconds. Data monitor does not fluctuate, go to step  22. Data monitor fluctuates less than 5 times, go to step  27.
    • Without CONSULT II -  Check that the MIL comes on more than 5 times during 10 seconds. MIL does not come on, go to step  22. MIL comes on less than 5 times, go to step  27.
  20. Check Heated Oxygen Sensor 1 (Bank 2) signal. Run engine at normal operating temperature to 2000 RPM for about 2 minutes under no-load. If testing is as specified, basic inspection is complete. If testing is not as specified, proceed accordingly:
    • With CONSULT II -  Check that the monitor fluctuates between Lean and Rich more than 5 times during 10 seconds. Data monitor does not fluctuate, go to step  22. Data monitor fluctuates less than 5 times, go to step  28.
    • Without CONSULT II -  Check that the MIL comes on more than 5 times during 10 seconds. MIL does not come on, go to step  22. MIL comes on less than 5 times, go to step  28.
  21. Check Heated Oxygen Sensor 1 (Bank 1) harness. Turn ignition switch off and disconnect battery ground cable, ECM harness connector and Heated Oxygen Sensor 1(Bank 1) harness connector. Continuity should exist after checking harness between ECM terminal 92 and Heated Oxygen Sensor 1 (Bank 2) terminal. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Checks should also be made for short-to-ground and short-to-power.

    If testing goes as specified, go to step  23. If testing does not go as specified, repair or replace as necessary. Go to step  4.

  22. Check Heated Oxygen Sensor 1 (Bank 2) harness. Turn ignition switch off and disconnect battery ground cable, ECM harness connector and Heated Oxygen Sensor 1 (Bank 2) harness connector. Continuity should exist after checking harness between ECM terminal 92 and Heated Oxygen Sensor 1 (Bank 2) terminal. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Checks should also be made for short-to-ground and short-to-power.

    If testing goes as specified, go to step  23. If testing does not go as specified, repair or replace as necessary. Go to step  4.

  23. Perform Accelerator Pedal Released position learning. See appropriate SELF DIAGNOSTICS article. If procedure okay, go to next step.
  24. Perform the Throttle Valve Closed Position Learning procedure. See appropriate SELF DIAGNOSTICS article. If procedure okay, go to next step.
  25. Perform Idle Air Volume Learning procedure. See appropriate SELF DIAGNOSTICS article. If result is okay, go to step  26. If result is incomplete, repeat as necessary, then go to step  4.
  26. Checking CO% requires engine to be started and warmed up until engine coolant temperature points to the middle of gauge. Once temperature reaches appropriate level, turn ignition switch off. Follow procedures accordingly:
    • With CONSULT II -  Select ENG COOLANT TEMP in ACTIVE TEST mode, then set ENG COOLANT TEMP to 41°F (5°C) by selecting DWN then Qd. Start engine and rev to 2000-3000 RPM, 2 or 3 times under no-load. Run engine at idle speed before checking CO%. Idle CO reads 0.7-9.9% with engine running smoothly. If results are okay, go to step  28. If results are not okay, go to step  27.
    • Without CONSULT II -  Disconnect engine coolant temperature sensor harness connector. Connect 4.4 kΩ resistor between terminals of engine coolant temperature sensor harness connector. Start engine and rev to 2000-3000 RPM, 2 or 3 times under no-load. Run engine at idle speed before checking CO%. Idle CO reads 0.7-9.9% with engine running smoothly. After checking CO%, turn off ignition switch off, then disconnect resistor from terminals of engine coolant temperature sensor harness connector, and then connect engine coolant temperature sensor harness connector to engine coolant temperature sensor. If results are okay, go to step  28. If results are not okay, go to step  27.
  27. Turn ignition switch off, then reconnect Heated Oxygen Sensor 1 harness connector. If procedure okay, go to step  29.
  28. Checking Heated Oxygen Sensor 1 (Bank 1)/(Bank 2) signal. Stop engine, then replace Heated Oxygen Sensor 1 on the malfunctioning bank. Follow procedures accordingly:
    • With CONSULT II -  Start engine and warm up until engine coolant temperature indicator points to middle of gauge. See HO2S1 MNTR (B1)/(B2) in DATA MONITOR mode. Run engine at 2000 RPM under no-load at normal operating temperatures. Check that the monitor fluctuates between LEAN & RICH more than 5 times during 10 seconds. If results are okay, go to step  4. If results are not okay, go to step  29.
    • Without CONSULT II -  Set ECM to Self-diagnostic mode II, Heated Oxygen Sensor 1 monitor. Switch the monitored sensor to the malfunctioning bank. Run engine at 2000 RPM under no-load at normal operating temperatures. Check to make sure MIL comes on more than 5 times during 10 seconds. If results are okay, go to step  4. If results are not okay, go to step  29.
  29. Detect malfunctioning part by checking the following:
    • Mass air flow sensor and its circuit, repair or replace if necessary.
    • Injector and its circuit, repair or replace if necessary.
    • Engine coolant temperature sensor and its circuit, repair or replace if necessary.
    • Fuel pressure and repair or replace if necessary.
    If results are okay, go to step  31. If results are not okay, repair or replace as necessary, then go to next step.
  30. After the inspection, unnecessary DTC might be displayed. Erase stored memory in ECM and TCM, then go to step  4.
  31. Substitute another known-good ECM to check ECM functionality. Go to step  4.
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