2010 Infiniti M45 BaseFACTORY 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 ECT Sensor
G04874984Courtesy of NISSAN MOTOR CO., U.S.A.

<Reference data>Β 

VOLTAGE AND RESISTANCE REFERENCE CHART

Engine coolant temperature [Β°C (Β°F)] Voltage(1) (V) Resistance (kΞ©)
-10 (14) 4.4 7.0 - 11.4
20 (68) 3.5 2.1 - 2.9
50 (122) 2.2 0.68 - 1.00
90 (194) 0.9 0.236 - 0.260
(1) This data is reference value and is measured between ECM terminal 73 (Engine coolant temperature sensor) and ground.
Fig 2: Resistance And Temperature Graph
G04874976Courtesy of NISSAN MOTOR CO., U.S.A.
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.