2004 Infiniti M45FACTORY OEM SERVICE PROCEDURE

Diagnostic Procedure

  1. Check Ground Connections 
    1. Turn ignition switch OFF.
    2. Loosen and retighten two ground screws. Refer to GROUND INSPECTION .
    1. OK or NG 
    2. OK: GO TO 2.
    3. NG: Repair or replace ground connections.
  2. Check Engine Coolant Temperature Sensor 

    Refer to COMPONENT INSPECTION .

    OK or NG 

    1. OK: GO TO 3.
    2. NG: Replace engine coolant temperature sensor.
  3. Check Thermostat Operation 

    When the engine is under cold [lower than 70°C (158°F)] condition, grasp lower radiator hose and confirm the engine coolant does not flow.

    OK or NG 

    1. OK: GO TO 4.
    2. NG: Repair or replace thermostat. Refer to THERMOSTAT AND WATER CONTROL VALVE .
  4. Check Intermittent Incident 

    Refer to TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT .

    1. : INSPECTION END 
Factory Service Tools

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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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