Century, Grand Prix, Impala, Intrigue, Lumina, Monte Carlo, Regal 2001-2005

Mass Air Flow Sensor

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NOTE
This is also known as the Intake Air Temperature (IAT) Sensor.

Operation



The primary function of the Air Intake System is to provide filtered air to the engine. The system uses a cleaner element mounted in a housing. The cleaner housing is remotely mounted and uses intake ducts to route the incoming air into the throttle body. The secondary function of the Air Intake System is to muffle air induction noise. This is achieved through the use of resonators attached to the air intake ducts. The resonators are tuned to the specific powertrain. The mass air flow (MAF)/intake air temperature (IAT) sensor is used to measure the temperature and the volume of the air entering the engine.

Removal & Installation



3.5L, 3.9L And 5.3L Engines
  1. Remove the air cleaner outlet duct.
  2.  
  3. Disconnect the MAF/IAT sensor electrical connector.
  4.  
  5. Remove the MAF/IAT sensor bolts. Remove the MAF/IAT sensor from the air cleaner housing
  6.  
  7. Remove the MAF/IAT sensor seal, if necessary.
  8.  
  9. To install, reverse removal procedure.

    Click image to see an enlarged view

    Fig. Removing mass air flow sensor-3.5L and 3.9L engines

  10.  

3.8L Engine
  1. Remove the fuel injector sight shield.
  2.  
  3. Disconnect the MAF/IAT sensor electrical connector (2)
  4.  
  5. Loosen the air cleaner intake duct clamps.
  6.  
  7. Remove the air cleaner intake duct from the air cleaner housing cover and the throttle body assembly.
  8.  
  9. Remove the MAF/IAT sensor from the air cleaner intake duct.
  10.  
  11. To install, reverse removal procedure.

    Click image to see an enlarged view

    Fig. Removing mass air flow sensor-3.8L engine

  12.  

Testing



Many intermittent open or shorted circuits come and go with harness and connector movement caused by vibration, engine torque, bumps and rough pavement, etc.

  1. Test the wiring harness and connectors by performing the following:

    Move the related connectors and wiring while monitoring the appropriate scan tool data.
     
    Move the related connectors and wiring with the component commanded ON and OFF, with the scan tool. Observe the components operation.
     
    With the engine running, move the related connectors and wiring while monitoring engine operation
     
    If harness or connector movement affects the data displayed, the component and system operation, or the engine operation, inspect and repair the harness or connections as necessary
     

  2.  
  3. Test the electrical connections and/or wiring by performing the following:

    Inspect for incorrect mating of the connector halves, or terminals not fully seated in the connector body, backed-out.
     
    Inspect for improperly formed or damaged terminals. Test for incorrect terminal tension.
     
    Inspect for poor terminal to wire connections including terminals crimped over insulation. This requires removing the terminal from the connector body.
     
    Inspect for corrosion or water intrusion. Pierced or damaged insulation can allow moisture to enter the wiring. The conductor can corrode inside the insulation with little visible evidence. Look for swollen and stiff sections of wire in the suspect circuits.
     
    Inspect for wires that are broken inside the insulation.
     

  4.  

 
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