Silverado 2008

Mass Air Flow (MAF) Sensor

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Location



Specific to:

Chevrolet Silverado 1500 2008

The Mass Air Flow (MAF) Sensor is integrated with the IAT sensor, it is located on the air cleaner assembly.

Operation



Specific to:

Chevrolet Silverado 1500 2008

Resistance changes in response to the ambient air temperature. The sensor has a negative temperature coefficient. As the temperature of the sensor rises the resistance across the sensor decreases. This provides a signal to the PCM indicating the temperature of the incoming air charge. This sensor helps the PCM to determine spark timing and air/fuel ratio. Information from this sensor is added to the pressure sensor information to calculate the air mass being sent to the cylinders. The IAT receives a 5-volt reference signal and the signal return is based upon the change in the measured resistance due to temperature.

Component Description

The Mass Air Flow (MAF) Sensor is a Positive Coefficient Thermistor (PTC) that determines the volume of air flowing into the intake system. The MAF Sensor operates within a 5 volt DC reference range, and provides a linear input signal to the Powertrain Control Module (PCM) that is based upon the measured engine intake air temperature. The thermistor, or -hot wire- is heated to a pre-determined temperature, and the then cools as the volume of air flowing past the wire increases. The PCM uses data from the MAF Sensor to calculate air-fuel mixture, ignition timing, and fuel injector pulse width. The MAF Sensor is sometimes integrated with the Intake Air Temperature (IAT) Sensor as a physical component.

Removal & Installation



4.3L, 4.8L, 5.3L And 6.0L Engines
  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Remove the air intake tube from the air cleaner assembly.

    Click image to see an enlarged view

    Fig. Air cleaner outlet resonator assembly-4.3L engines



    Click image to see an enlarged view

    Fig. Air cleaner outlet resonator assembly-4.8L, 5.3L & 6.0L engines

  6.  
  7. Detach the electrical connector from the MAF sensor.
  8.  
  9. Loosen the sensor seal clamp.
  10.  
  11. Remove the sensor from its mounting.
    NOTE
    On the 4.8L, 5.3L, 6.0L engines, the embossed arrow located on the sensor indicated proper air flow direction.



    Click image to see an enlarged view

    Fig. IAT/MAF sensor electrical connector-4.3L engines



    Click image to see an enlarged view

    Fig. IAT/MAF sensor and related components-4.3L engines



    Click image to see an enlarged view

    Fig. IAT/MAF sensor and related components-4.8L, 5.3L & 6.0L engines

  12.  

To install:


NOTE
Be sure to use new fasteners, as required.

  1. Position the sensor on its mounting.
  2.  
  3. Continue the installation in the reverse order of the removal procedure.
  4.  

Testing



Specific to:

Chevrolet Silverado 1500 2008


NOTE
Refer to the Electrical Wiring Diagram for component and connector locations, connector views, and circuit-specific information.

MAF Circuit Testing

Specific to:

Chevrolet Silverado 1500 2008

Use a suitable scan tool, a Graphing Multi-Meter (GMM), or a Digital Volt-Ohm Meter (DVOM) in order to view the MAF data.

MAF Sensor logic is relative to the scale of resistance: when the intake air volume is low, the voltage is decreased. When the coolant temperature is high, the voltage is increased.

Inspect the air intake tube, the engine air filter, and the MAF and/or IAT sensors for contamination and physical damage in order to verify that the air induction system is in proper working order. If an air induction system fault is evident, repair as required before continuing.

If a DVOM is being used, additional information may be acquired by taking measurements at the sensor connector as well as the PCM connector. If a significant voltage drop is measured (greater than 0.5 volts DC), check the wiring harness and connections for corrosion, poor pin connections, or damaged wires.

If all engine wiring and pin connections are confirmed, disconnect the MAF Sensor to verify the signal with a DVOM, and verify PCM communication before replacing the MAF Sensor.

Click image to see an enlarged view

Fig. MAF Sensor Range Chart

MAF Sensor Strategy

Specific to:

Chevrolet Silverado 1500 2008

The MAF Sensor provides a linear input signal (See Figure 1) to the Powertrain Control Module (PCM) for a number of engine control system calculations. The MAF signal is compared with Manifold Absolute Pressure (MAP), Intake Air Temperature (IAT), Engine Coolant Temperature (ECT), and Fuel Trim (HO2S) in order to determine the correct air-fuel mixture for measured operating conditions.

Related Diagnostic Trouble Codes

Specific to:

Chevrolet Silverado 1500 2008



Click image to see an enlarged view

Fig. Related Diagnostic Trouble Codes

 
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