Nissan X-Trail T31 temperature sensor: where is it located, how to check and replace

Nissan X-Trail T31 (2007–2013) is equipped with several temperature sensors, which determine the correct operation of the engine, climate control and cooling system. But when the engine starts to overheat, the fan does not turn on or the dashboard lights up error P0115, owners are wondering: where is this sensor located and how to check it?

In this article we will analyze exact locations all temperature sensors in X-Trail T31 (including coolant, air and interior temperature sensor), we present unique photos showing fastenings, and we’ll also tell you how to diagnose faults without visiting a service station. We will pay special attention to the nuances of replacement - for example, why after installing a new sensor it may be necessary to reset errors via CONSULT-III.

What temperature sensors are there in the Nissan X-Trail T31

B Nissan X-Trail T31 minimum is used three types of temperature sensors, each of which is responsible for its own function:

• 🔹 Coolant temperature (ECT) sensor — transmits data to the ECU to adjust the fuel mixture and control the fan.
• 🔹 Intake Air Temperature (IAT) Sensor - affects the operation of the injection system and turbine (on models with MR20DD And QR25DE).
• 🔹 Interior temperature sensor — used by climate control to automatically adjust airflow.

Most often, problems arise with the first type - ECT (Engine Coolant Temperature sensor). Its malfunction leads to:

• 🚨 Floating revolutions at idle speed.
• 🚨 The Check Engine light comes on with codes P0115–P0118.
• 🚨 Uncontrolled fan activation or its complete refusal.

Air temperature sensor (IAT) is usually integrated into MAF sensor (mass air flow sensor) or installed separately in the air duct. Its failure leads to over-enrichment of the mixture and increased fuel consumption.

Where is the coolant temperature (ECT) sensor located?

B Nissan X-Trail T31 coolant temperature sensor located on cylinder head, next to the thermostat. The exact location depends on the engine type:

On all modifications the sensor has single-pin connector (except diesel) with a characteristic green or black body. approaches him purple with white stripe wire (signal) and black (mass).

How to find ECT visually:

1. Remove decorative engine cover (if any).
2. Follow upper radiator pipe — it leads to the thermostat, and next to it there will be a sensor.
3. Look for an element with metal thread and plastic connector, to which a pair of wires fits.

⚠️ Attention: On diesel X-Trail T31 (M9R) coolant temperature sensor is often confused with fuel temperature sensor, which is located on the fuel rail. The latter has three-pin connector and does not affect the operation of the fan.

Intake Air Temperature (IAT) Sensor Location

Sensor IAT (Intake Air Temperature) X-Trail T31 maybe:

• 🔧 Built into MAF sensor (on most petrol versions).
• 🔧 Installed separately in the air duct between the air filter and the throttle (rarely, for example, on early QR25DE).

How to find IAT:

1. Open the hood and find air filter box.
2. Follow air duct corrugation - the sensor will be located on it or on the MAF sensor (black plastic box with 5-pin connector).
3. IAT has two wires: usually gray (signal) and black (mass).

On diesel X-Trail T31 (M9R) air temperature sensor is integrated into absolute pressure sensor (MAP-sensor), which is located on the intake manifold.

⚠️ Attention: If on your X-Trail T31 After 2010 the IAT sensor is not detected separately - don't panic. On later versions it is always built in MAF, and replacement requires purchasing the entire assembly.

Interior temperature sensor: where to look and how to check

Interior temperature sensor Nissan X-Trail T31 responsible for the work climate control and located:

• 📍 On the ceiling, next to the lampshade (on most versions).
• 📍 In the center console, under the climate control panel (on cars with automatic climate control).

How to identify it:

• 🔍 Has small plastic case (the size of a coin).
• 🔍 Comes up to him two-core wire (usually gray and black).
• 🔍 Often closed decorative grille for free access of air.

To check the sensor:

1. Remove the plastic headliner or panel (depending on location).
2. Disconnect the connector and measure the resistance with a multimeter:
   • 🌡️ At +20°C: ~2–3 kOhm.
   • 🌡️ At +30°C: ~1–1.5 kOhm.

Signs of malfunctioning temperature sensors

Failure of temperature sensors in X-Trail T31 manifests itself differently depending on the type of sensor. Let's consider key symptoms:

The most reliable diagnostic method is resistance check multimeter. For example, for ECT:

• 📊 At +20°C: ~2–3 kOhm.
• 📊 At +80°C: ~200–300 Ohm.
• 📊 When boiling (+100°C): ~100 Ohm.

If the resistance is not normal or does not change when heated, the sensor must be replaced.

How to replace the coolant temperature sensor in the X-Trail T31: step-by-step instructions

Replacement ECT on Nissan X-Trail T31 does not require special skills, but there are nuances. For example, on QR25DE You will have to remove the throttle assembly to gain access.

Drain some of the coolant (to a level below the sensor)|Disconnect the negative terminal from the battery|Prepare a new sensor (article: 22630-4M000 for gasoline, 22630-EA20A for diesel)|Have a torque wrench on hand (tightening torque: 15–20 Nm)-->

Step by step process:

1. Drain the antifreeze:
   • Place a container under the radiator drain hole.
   • Unscrew the plug and drain ~1 liter of liquid (to a level below the sensor).
2. Remove the old sensor:
   • Disconnect the connector by pressing the latch.
   • Key on 19 mm (or 22 mm for diesel) unscrew the sensor.
   • Be prepared for antifreeze to flow - cover the generator with a rag.
3. Install a new sensor:
   • Apply to thread sealant-fixer (For example, Loctite 577).
   • Screw the sensor firmly 15–20 Nm (Tightening can cause damage to the cylinder head!).
   • Connect the connector until it clicks.

1. Залейте жидкость до максимума в расширительном бачке.
2. Заведите двигатель, прогрейте до рабочей температуры.
3. Несколько раз сожмите верхний патрубок радиатора для удаления воздуха.

After replacement be sure to clear errors via a scanner (for example, ELM327 + program Torque Pro). On diesel versions it may be necessary ECU adaptation through CONSULT-III.

⚠️ Attention: On X-Trail T31 with engine MR20DD after replacing ECT the settings sometimes get lost valve timing. If the code appears P0011 — throttle valve training is required (the procedure is described in the service manual).

Common replacement mistakes and how to avoid them

Even experienced car owners make mistakes when working with temperature sensors in X-Trail T31. Here top 5 misses and how to prevent them:

• 🔧 Using the wrong sensor:

  Installed on petrol and diesel versions different ECT (differ in resistance and connector). For example, a sensor from QR25DE not suitable for M9R.

• 🔧 Thread retightening:

  Tightening torque - maximum 20 Nm. Excess leads to cracks in the cylinder head (especially on aluminum blocks MR20DD).

• 🔧 Ignoring sealant:

  Without a thread locker, the sensor may unscrew itself or skip antifreeze. Use Loctite 577 or Permatex 56521.

• 🔧 Incorrect air removal:

  If you do not bleed air from the system, the engine will overheat. On X-Trail T31 for this you need accelerate several times at idle speed with the expansion tank cap open.

• 🔧 Forgetting to reset errors:

  Even after replacing the sensor Check Engine may remain on until the errors are erased by the scanner.

Another common problem is connector damage when disconnected. On X-Trail T31 the clamps are fragile, so squeeze them out carefully flat screwdriver.

FAQ: Frequently asked questions about temperature sensors in Nissan X-Trail T31