Ram Truck 1500, 2500 & 3500 (2006-2008)

Mass Air Flow Sensor

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Operation



6.7L Diesel Engine

The Mass Airflow (MAF) sensor is a frequency based device. A constant voltage is applied to a heated wire on the sensor. This wire is positioned in the air cleaner air stream and is heated by the electrical current that the voltage produces. As air flows across it, it cools down. The heated wire or film is a positive temperature coefficient resistor. This means that its resistance drops when its temperature drops. The drop in resistance allows more current to flow through it in order to maintain the programmed temperature. This current is changed to a frequency which is sent to the Engine Control Module (ECM) and interpreted as air flow. Adjustments for air temperature and humidity are taken into consideration because they also affect the temperature of the heated wire or film.

Removal & Installation



6.7L Diesel Engine
  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Disconnect the electrical connector at Mass Airflow (MAF) sensor.
  4.  
  5. Remove two mounting screws.
  6.  
  7. Remove the MAF sensor from air cleaner cover.
  8.  

To install:

  1. Check condition of sensor O-ring.
  2.  
  3. Position the MAF sensor into top of air cleaner cover with a slight twisting action.
  4.  
  5. Install the mounting screw.
  6.  
  7. Install the MAF sensor electrical connector.
  8.  

Testing



6.7L Diesel Engine

Checking for low voltage to the Mass Airflow (MAF) sensor as follows:

  1. Turn the ignition on, engine not running.
  2.  
  3. Install scan tool.
  4.  
  5. Check to see if there are any EGR airflow control valve, turbocharger actuator, or smart power relay faults. Troubleshoot them first.
  6.  
  7. Turn the ignition off.
  8.  
  9. Disconnect the MAF Sensor harness connector
  10.  
  11. Turn the ignition on, engine not running.
  12.  
  13. Measure the voltage between the F348 (Pin 2) smart power relay feed circuit and K916 (Pin 3) return circuit of the Mass Air Flow sensor harness connector. The reading should be equal to the battery voltage.
  14.  
  15. If the reading was not as stated check for an open or short condition.
  16.  
  17. If battery voltage was present, turn off the ignition.
  18.  
  19. Reconnect the disconnected MAF sensor harness connector.
  20.  
  21. Turn the ignition on, engine not running.
  22.  
  23. Disconnect the MAF Sensor harness connector.
  24.  
  25. With the scan tool, read DTC's.
  26.  
  27. If the DTC P0103 is present suspect a faulty MAF sensor.

    Click image to see an enlarged view

    Fig. The Mass Airflow (MAF) sensor harness connector 6.7L diesel engine

  28.  

 
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