Malibu, Malibu MAXX 2006-2008

Mass Air Flow Sensor

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Operation



The Mass Air Flow (MAF) sensor is integrated with the Intake Air Temperature (IAT) sensor. The MAF sensor is an air flow meter that measures the amount of air entering the engine. The engine control module (ECM) uses the MAF sensor signal to provide the correct fuel delivery for all engine speeds and loads. A small quantity of air entering the engine indicates a deceleration or idle condition. A large quantity of air entering the engine indicates an acceleration or high load condition. The MAF/IAT sensor has an ignition 1 voltage circuit, a ground circuit, a MAF sensor signal circuit, and IAT sensor signal circuit, and a low reference circuit.

The ECM applies 5 volts to the MAF sensor on the MAF sensor signal circuit. The sensor uses the voltage to produce a frequency based on the inlet air flow through the sensor bore. The frequency varies in a range of near 2,000 Hertz at idle to near 10,000 Hertz at maximum engine load.

Removal & Installation



2.2L (L61) Engine
  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Disconnect the engine wiring harness electrical connector from the Mass Air Flow (MAF) sensor.
  4.  
  5. Remove the MAF sensor screws.
  6.  
  7. Remove the MAF sensor from the air cleaner cover.

    Click image to see an enlarged view

    Fig. Mass Air Flow (MAF) sensor removal

  8.  

To install:

  1. Install the MAF sensor and screws to the air cleaner cover.
  2.  
  3. Tighten the mounting screws to 5 inch. lbs. (0.6 Nm).
  4.  
  5. Connect the engine wiring harness electrical connector to the MAF sensor.
  6.  

3.5L (LZ4) & 3.9L (LZ9) Engines
  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Remove the air cleaner outlet duct.
  4.  
  5. Disconnect the engine wiring harness electrical connector from the Mass Air Flow (MAF)/Intake Air Temperature (IAT) sensor.
  6.  
  7. Remove the MAF/IAT sensor screws (1).
  8.  
  9. Remove the MAF/IAT sensor (2).
  10.  
  11. Remove and discard the MAF/IAT sensor O-ring seal.

    Click image to see an enlarged view

    Fig. Mass Air Flow (MAF)/Intake Air Temperature (IAT) sensor removal

  12.  

To install:

  1. Install the new MAF/IAT sensor O-ring seal.
  2.  
  3. Install the MAF/IAT sensor screws and tighten to 44 inch. lbs. (1.5 Nm).
  4.  
  5. Connect the engine wiring harness electrical connector to the MAF/IAT sensor.
  6.  
  7. Install the air cleaner outlet duct.
  8.  

Testing



To determine if the ECM can properly process the MAF sensor frequency signal, connect the J 38522 variable signal generator to the vehicle as follows:



Turn OFF the ignition
 
Connect the battery voltage supply, and ground the black lead.
 
Connect the red lead to the signal circuit terminal A.
 
Set the duty cycle switch to Normal.
 
Set the Frequency switch to 5 K.
 
Set the signal switch to 5 volts.
 
Start the engine.
 
Observe the MAF Sensor parameter for the correct range of 4,950-5,025 Hz.
 

  1. If the MAF Sensor parameter is not within the specified range, replace the ECM.
  2.  
  3. If the MAF Sensor parameter is within the specified range, replace the MAF sensor.

    Click image to see an enlarged view

    Fig. Variable signal generator J 38522 shown



    Click image to see an enlarged view

    Fig.

  4.  

 
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