BMW Cars 1999-06

Intake Air Temperature (IAT) Sensor 1

Imprimir

Operation



The Intake Air Temperature (IAT) sensor, much like the Engine Coolant Temperature (ECT) sensor is referred to as an NTC (Negative Temperature Coefficient) type sensor, meaning as the temperature increases, electrical resistance of the sensor decreases.

The Engine Control Module (ECM) uses the IAT sensor signal as a correction factor for fuel injection pulse width and ignition timing. The sensor is located as follows:



M20, M42 and S14 engines with a vane type Mass Air Flow (MAF): inside the MAF housing
 
M44 engines: in the front of the upper air filter housing
 
M50 and S50 engines: on the side of the intake manifold near the throttle body
 
M52 and S52 engines: on the bottom of the intake manifold near the throttle body
 



Click image to see an enlarged view

Fig. The air temperature sensor is located next to the throttle body on the intake manifold-M50 engine

Removal & Installation




CAUTION
Make sure that the ignition is switched off and no electrical equipment is on or running.

  1. Access the fault memory of control unit of Digital Motor Electronics (DME), check for any stored fault messages, rectify those faults and clear the fault memory.
  2.  
  3. Remove the cover from the fuel injectors.
  4.  
  5. Disconnect the plug connection for temperature sensor.

    Click image to see an enlarged view

    Fig. Disconnect the plug connection (1) for temperature sensor

  6.  
  7. Press down on the catch spring and remove the temperature sensor from intake air manifold.
  8.  

To install:

  1. Check the sealing ring on temperature sensor for damage and replace it if necessary.
  2.  
  3. Before installing the sensor, coat the sealing ring with an anti-seize material.
  4.  
  5. Press down on the catch spring and replace the temperature sensor

    Click image to see an enlarged view

    Fig. Press down on the catch spring and replace the temperature sensor

  6.  


CAUTION
Make sure that the ignition is switched off and no electrical equipment is on or running.

  1. Access the fault memory of control unit of Digital Motor Electronics (DME), check for any stored fault messages, rectify those faults and clear the fault memory.
  2.  
  3. Remove the throttle valve neck, but the cables and throttle valve preheating unit remains connected.

    Click image to see an enlarged view

    Fig. Disconnect the plug connection on temperature sensor (arrow)

  4.  
  5. Depress interlock button (1), unclip temperature sensor and remove from intake air manifold.
  6.  

To install:

  1. Depress interlock button, and return the temperature sensor to the intake air manifold.
  2.  
  3. Connect the plug connection on the temperature sensor.

    Click image to see an enlarged view

    Fig. Depress the interlock button and attach temperature sensor

  4.  


CAUTION
Make sure that the ignition is switched off and no electrical equipment is on or running.

  1. Access the fault memory of control unit of Digital Motor Electronics (DME), check for any stored fault messages, rectify those faults and clear the fault memory.
  2.  
  3. Remove the cover from the fuel injectors.
  4.  
  5. Disconnect the plug connection for temperature sensor.

    Click image to see an enlarged view

    Fig. Disconnect the plug connection (1) for temperature sensor

  6.  
  7. Press down on the catch spring and remove the temperature sensor from intake air manifold.
  8.  

To install:

  1. Check the sealing ring on temperature sensor for damage and replace it if necessary.
  2.  
  3. Before installing the sensor, coat the sealing ring with an anti-seize material.
  4.  
  5. Press down on the catch spring and replace the temperature sensor

    Click image to see an enlarged view

    Fig. Press down on the catch spring and replace the temperature sensor

  6.  


CAUTION
Make sure that the ignition is switched off and no electrical equipment is on or running.

  1. Access the fault memory of control unit of Digital Motor Electronics (DME), check for any stored fault messages, rectify those faults and clear the fault memory.
  2.  
  3. For cars equipped with an acoustic cover that is screwed down, remove the seal caps and unfasten the nuts.
  4.  
  5. For cars equipped with an acoustic cover that is held in place with press stud fasteners, open the press-studs one at a time, while lifting the acoustic cover slightly on all four corners. Once all four press-studs have been opened, remove the acoustic cover.
  6.  
  7. The temperature sensor is clipped into the upper section of intake filter housing.
  8.  
  9. Disconnect connector.
  10.  
  11. Press locking unit and remove temperature sensor.

    Click image to see an enlarged view

    Fig. Press down on the locking unit (1) and remove the temperature sensor (2)

  12.  

To install:

  1. Replace the temperature sensor and lock the clip into place.
  2.  
  3. Plug in the connector.
  4.  


CAUTION
Make sure that the ignition is switched off and no electrical equipment is on or running.

  1. Access the fault memory of control unit of Digital Motor Electronics (DME), check for any stored fault messages, rectify those faults and clear the fault memory.
  2.  
  3. For cars equipped with an acoustic cover that is screwed down, remove the seal caps and unfasten the nuts.
  4.  
  5. For cars equipped with an acoustic cover that is held in place with press stud fasteners, open the press-studs one at a time, while lifting the acoustic cover slightly on all four corners. Once all four press-studs have been opened, remove the acoustic cover.
  6.  
  7. The temperature sensor is clipped into the upper section of intake filter housing.
  8.  
  9. Disconnect connector.
  10.  
  11. Press locking unit and remove temperature sensor.

    Click image to see an enlarged view

    Fig. Press down on the locking unit (1) and remove the temperature sensor (2)

  12.  

To install:

  1. Replace the temperature sensor and lock the clip into place.
  2.  
  3. Plug in the connector.
  4.  


CAUTION
Make sure that the ignition is switched off and no electrical equipment is on or running.

  1. Access the fault memory of control unit of Digital Motor Electronics (DME), check for any stored fault messages, rectify those faults and clear the fault memory.
  2.  
  3. Press down on the retaining spring.
  4.  
  5. Remove the connector.
  6.  
  7. Unclip and remove the temperature sensor.
  8.  

To install:

Click image to see an enlarged view

Fig. The connector and the retaining spring for the sensor

  1. Replace the temperature sensor and clip it into place
  2.  
  3. Plug in the connector .
  4.  
  5. Attach the retaining spring.
  6.  


CAUTION
Make sure that the ignition is switched off and no electrical equipment is on or running.

  1. Access the fault memory of control unit of Digital Motor Electronics (DME), check for any stored fault messages, rectify those faults and clear the fault memory.
  2.  
  3. Remove the throttle valve neck, but the cables and throttle valve preheating unit remains connected.

    Click image to see an enlarged view

    Fig. Disconnect the plug connection on temperature sensor (arrow)

  4.  
  5. Depress interlock button (1), unclip temperature sensor and remove from intake air manifold.
  6.  

To install:

  1. Depress interlock button, and return the temperature sensor to the intake air manifold.
  2.  
  3. Connect the plug connection on the temperature sensor.

    Click image to see an enlarged view

    Fig. Depress the interlock button and attach temperature sensor

  4.  


CAUTION
Make sure that the ignition is switched off and no electrical equipment is on or running.

  1. Access the fault memory of control unit of Digital Motor Electronics (DME), check for any stored fault messages, rectify those faults and clear the fault memory.
  2.  
  3. Remove the throttle valve neck, but the cables and throttle valve preheating unit remains connected.

    Click image to see an enlarged view

    Fig. Disconnect the plug connection on temperature sensor (arrow)

  4.  
  5. Depress interlock button (1), unclip temperature sensor and remove from intake air manifold.
  6.  

To install:

  1. Depress interlock button, and return the temperature sensor to the intake air manifold.
  2.  
  3. Connect the plug connection on the temperature sensor.

    Click image to see an enlarged view

    Fig. Depress the interlock button and attach temperature sensor

  4.  


CAUTION
Make sure that the ignition is switched off and no electrical equipment is on or running.

  1. Access the fault memory of control unit of Digital Motor Electronics (DME), check for any stored fault messages, rectify those faults and clear the fault memory.
  2.  
  3. Remove the cover from the fuel injectors.
  4.  
  5. Disconnect the plug connection for temperature sensor.

    Click image to see an enlarged view

    Fig. Disconnect the plug connection (1) for temperature sensor

  6.  
  7. Press down on the catch spring and remove the temperature sensor from intake air manifold.
  8.  

To install:

  1. Check the sealing ring on temperature sensor for damage and replace it if necessary.
  2.  
  3. Before installing the sensor, coat the sealing ring with an anti-seize material.
  4.  
  5. Press down on the catch spring and replace the temperature sensor

    Click image to see an enlarged view

    Fig. Press down on the catch spring and replace the temperature sensor

  6.  


CAUTION
Make sure that the ignition is switched off and no electrical equipment is on or running.

  1. Access the fault memory of control unit of Digital Motor Electronics (DME), check for any stored fault messages, rectify those faults and clear the fault memory.
  2.  
  3. Disconnect the plug connection on the temperature sensor.

    Click image to see an enlarged view

    Fig. Disconnect the plug connection on temperature sensor (1)

  4.  
  5. Depress interlock button (1), unclip temperature sensor and remove from intake air manifold.
  6.  

To install:

  1. Depress interlock button, and return the temperature sensor to the intake air manifold.
  2.  
  3. Connect the plug connection on the temperature sensor.

    Click image to see an enlarged view

    Fig. Depress the interlock button (1) and attach temperature sensor

  4.  


CAUTION
Make sure that the ignition is switched off and no electrical equipment is on or running.

  1. Access the fault memory of control unit of Digital Motor Electronics (DME), check for any stored fault messages, rectify those faults and clear the fault memory.
  2.  
  3. Remove the cover from the fuel injectors.
  4.  
  5. Disconnect the plug connection for temperature sensor.

    Click image to see an enlarged view

    Fig. Disconnect the plug connection (1) for temperature sensor

  6.  
  7. Press down on the catch spring and remove the temperature sensor from intake air manifold.
  8.  

To install:

  1. Check the sealing ring on temperature sensor for damage and replace it if necessary.
  2.  
  3. Before installing the sensor, coat the sealing ring with an anti-seize material.
  4.  
  5. Press down on the catch spring and replace the temperature sensor

    Click image to see an enlarged view

    Fig. Press down on the catch spring and replace the temperature sensor

  6.  

2.5L (M52) Engines

CAUTION
Make sure that the ignition is switched off and no electrical equipment is on or running.

  1. Access the fault memory of control unit of Digital Motor Electronics (DME), check for any stored fault messages, rectify those faults and clear the fault memory.
  2.  
  3. Remove the cover from the fuel injectors.
  4.  
  5. Disconnect the plug connection for temperature sensor.

    Click image to see an enlarged view

    Fig. Disconnect the plug connection (1) for temperature sensor

  6.  
  7. Press down on the catch spring and remove the temperature sensor from intake air manifold.
  8.  

To install:

  1. Check the sealing ring on temperature sensor for damage and replace it if necessary.
  2.  
  3. Before installing the sensor, coat the sealing ring with an anti-seize material.
  4.  
  5. Press down on the catch spring and replace the temperature sensor

    Click image to see an enlarged view

    Fig. Press down on the catch spring and replace the temperature sensor

  6.  

2.5L (M52TU) Engines

CAUTION
Make sure that the ignition is switched off and no electrical equipment is on or running.

  1. Access the fault memory of control unit of Digital Motor Electronics (DME), check for any stored fault messages, rectify those faults and clear the fault memory.
  2.  
  3. Remove the cover from the fuel injectors.
  4.  
  5. Disconnect the plug connection for temperature sensor.

    Click image to see an enlarged view

    Fig. Disconnect the plug connection (1) for temperature sensor

  6.  
  7. Press down on the catch spring and remove the temperature sensor from intake air manifold.
  8.  

To install:

  1. Check the sealing ring on temperature sensor for damage and replace it if necessary.
  2.  
  3. Before installing the sensor, coat the sealing ring with an anti-seize material.
  4.  
  5. Press down on the catch spring and replace the temperature sensor

    Click image to see an enlarged view

    Fig. Press down on the catch spring and replace the temperature sensor

  6.  

2.8L (M52) And 3.2L (S52) Engines

CAUTION
Make sure that the ignition is switched off and no electrical equipment is on or running.

  1. Access the fault memory of control unit of Digital Motor Electronics (DME), check for any stored fault messages, rectify those faults and clear the fault memory.
  2.  
  3. Remove the throttle valve neck, but the cables and throttle valve preheating unit remains connected.

    Click image to see an enlarged view

    Fig. Disconnect the plug connection on temperature sensor (arrow)

  4.  
  5. Depress interlock button (1), unclip temperature sensor and remove from intake air manifold.
  6.  

To install:

  1. Depress interlock button, and return the temperature sensor to the intake air manifold.
  2.  
  3. Connect the plug connection on the temperature sensor.

    Click image to see an enlarged view

    Fig. Depress the interlock button and attach temperature sensor

  4.  

2.8L (M52) Engines

CAUTION
Make sure that the ignition is switched off and no electrical equipment is on or running.

  1. Access the fault memory of control unit of Digital Motor Electronics (DME), check for any stored fault messages, rectify those faults and clear the fault memory.
  2.  
  3. Remove the throttle valve neck, but the cables and throttle valve preheating unit remains connected.

    Click image to see an enlarged view

    Fig. Disconnect the plug connection on temperature sensor (arrow)

  4.  
  5. Depress interlock button (1), unclip temperature sensor and remove from intake air manifold.
  6.  

To install:

  1. Depress interlock button, and return the temperature sensor to the intake air manifold.
  2.  
  3. Connect the plug connection on the temperature sensor.

    Click image to see an enlarged view

    Fig. Depress the interlock button and attach temperature sensor

  4.  

 
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