2004 Infiniti FX45FACTORY OEM SERVICE PROCEDURE

Component Description

The engine COOLANT temperature sensor is used to detect the engine COOLANT temperature. The sensor modifies a voltage signal from the ECM. The modified signal returns to the ECM as the engine COOLANT temperature input. The sensor uses a thermistor which is sensitive to the change in temperature. The electrical resistance of the thermistor decreases as temperature increases.

Fig 1: Identifying Engine COOLANT Temperature Sensor Components
G00344676Courtesy of NISSAN MOTOR CO., U.S.A.

Reference dataΒ 

Fig 2: Identifying Engine COOLANT Temperature Sensor Thermistor Specifications
G00344677Courtesy of NISSAN MOTOR CO., U.S.A.

For thermistor specifications in graph format, see Figure .

CAUTION: Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in damage to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
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:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.

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