Automobile Repair/Nissan/Maxima (4th Generation)/Replacing the engine coolant temperature sensor

The Engine Coolant Temperature Sensor is a small thermometer, that reads the coolant temperature and transmits that information to the ECU (cars computer). This should not be confused with the Thermal Transmitter, that sends the coolant temperature to the dash board. The Engine Coolant Temperature Sensor should only be replaced if your ECU is showing a coolant temperature code and your coolant temperature is fine.

Tools/Parts neededEdit

  • A medium size adjustable wrench
  • A Phillips-head screw driver
  • A new Engine Coolant Temperature Sensor


  1. If you have a stock intake, remove air box by losing the Phillips-head hose clamp.
  2. Then remove the intake duck, by removing the two Phillips-heads attached to the front of the car and pull it out.
  3. Now look just to the right of the engine, at the hose that comes out of the engine, it connected to a sort pipe. There are two wires going into it, the one closest to you is the thermal transmitter and the one just behind it is the Coolant Temperature sensor.
  4. Remove the cable from the Coolant Temperature Sensor, you have to push the tab in to get it off (if your having trouble use a screw driver to push it in).
  5. Now use your medium size adjustable wrench, to remove the Coolant Temperature Sensor (don't worry no antifreeze will not come out).
  6. Install the new one with your adjustable wrench and reattach the wire.
  7. Now reinstall the intake duck and the air box making sure the Phillips-heads are tight.