Nissan Sentra/Pulsar/NX 1982-1996 Repair Guide

Mass Air Flow (MAF) Sensor

Print

OPERATION



See Figures 1, 2 and 3



Click image to see an enlarged view

Fig. Fig. 1: Mass air flow sensor with throttle body fuel injection



Click image to see an enlarged view

Fig. Fig. 2: Operation of a film type air flow sensor with throttle body fuel injection



Click image to see an enlarged view

Fig. Fig. 3: Mass air flow sensor with multi-point fuel injection

All Sentra/Pulsar fuel injected engines, except the E15ET engine use a MAF sensor input to calculate engine load. The sensor is mounted either in the air cleaner housing on MFI engines or in the throttle body housing on TBI engines.

The MAF uses a heated wire or film which is stretched across the incoming air flow. The element requires more electrical current to maintain its temperature, as the amount of intake air flow increases. By measuring the amount of current necessary to maintain the temperature of the wire or film, the control unit can calculate the volume of air entering the engine. Since the volume of air entering the engine is directly proportional to the amount of engine load, the ECM can determine the operating load of the engine, by monitoring the MAF signal wire.

TESTING



E16i Engine
METHOD A

See Figure 4



Click image to see an enlarged view

Fig. Fig. 4: ECM connector terminal identification-E16i engine

  1. Pull back the mass air flow sensor harness protective cover, exposing the wire terminal ends.
  2.  
  3. Turn the ignition ON .
  4.  
  5. Connect a voltmeter between MAF sensor connector E and a known good engine. Battery voltage should exist.

    If battery voltage does not exist, check the MAF sensor power supply circuitry.
     
    If battery voltage does exist, proceed to the next step.
     

  6.  
  7. Connect a voltmeter between ECM connector 31 and a known good engine ground.
  8.  
  9. Start the engine and allow it to fully warm up before continuing.
  10.  
  11. The voltage reading should change by racing the engine with the accelerator pedal, from 0 to approximately 5.0 volts. If the voltage is not as specified, check the wiring between the MAF sensor and the ECM. If the wiring is okay, replace the MAF sensor.
  12.  

METHOD B

See Figure 5



Click image to see an enlarged view

Fig. Fig. 5: Testing the mass air flow sensor, with the sensor removed-E16i engine

  1. Remove the MAF sensor from the vehicle.
  2.  
  3. Connect positive (+) battery voltage to sensor terminal E . Connect terminal C to battery ground (-).
  4.  
  5. Connect a voltmeter between sensor terminals A and D . The meter should read 1.5-2.0 volts.

    If battery voltage was within specifications, proceed to the next step.
     
    If battery voltage was not within specifications, replace the MAF sensor.
     

  6.  
  7. With the meter and battery connected as in the previous step, blow across the sensor film. The meter should read between 2.5-4.0 volts. If the reading is not within specifications, replace the MAF sensor.
  8.  

CA16DE Engine

See Figure 6



Click image to see an enlarged view

Fig. Fig 6: ECM connector terminal identification-CA16DE engine

  1. Visually inspect the MAF sensor hot wire for dirt, dust, or damage. Clean or replace if necessary.
  2.  
  3. Pull back the mass air flow sensor harness protective cover, exposing the wire terminal ends.
  4.  
  5. Turn the ignition ON .
  6.  
  7. Connect a voltmeter between MAF sensor connector B and a known good engine. Battery voltage should exist.

    If battery voltage does not exist, check MAF sensor power supply circuitry.
     
    If battery voltage does exist, proceed to the next step.
     

  8.  
  9. Connect a voltmeter between ECM connector 31 and a known good engine ground.
  10.  
  11. Start the engine and allow it to fully warm up before continuing.
  12.  
  13. The voltage reading should be approximately 1.5 volts at idle. If the voltage is not as specified, check the wiring between the MAF sensor and the ECM. If the wiring is okay, replace the MAF sensor.
  14.  

GA16i and CA18DE Engines

See Figures 7, 8 and 9



Click image to see an enlarged view

Fig. Fig. 7: Mass air flow sensor connector terminal identification-GA16i engine



Click image to see an enlarged view

Fig. Fig. 8: Mass air flow sensor connector terminal identification-CA18DE engine



Click image to see an enlarged view

Fig. Fig. 9: ECM connector terminal identification-GA16i and CA18DE engines

  1. Visually inspect the MAF sensor hot wire for dirt, dust, or damage. Clean or replace if necessary.
  2.  
  3. Pull back the mass air flow sensor harness protective cover, exposing the wire terminal ends.
  4.  
  5. Turn the ignition ON .
  6.  
  7. Connect a voltmeter between the MAF sensor connector B and a known good engine. Battery voltage should exist.

    If battery voltage does not exist, check MAF sensor power supply circuitry.
     
    If battery voltage does exist, proceed to the next step.
     

  8.  
  9. Connect a voltmeter between ECM connector 15 and a known good engine ground.
  10.  
  11. Start the engine. Allow the engine to fully warm up before continuing.
  12.  
  13. The voltage reading at idle should be approximately 1.0 volt for the GA16i engine, or 1.5 volts for the GA18DE engine. If the voltage is out of range, before replacing the sensor, check the wiring between the MAF sensor and the ECM.
  14.  

1.6L (GA16DE) and 2.0L (SR20DE) Engines

See Figures 10, 11, 12, 13, 14, 15, 16 and 17



Click image to see an enlarged view

Fig. Fig. 10: Mass air flow sensor connector terminal identification-1991-94 GA16DE engine



Click image to see an enlarged view

Fig. Fig. 11: Mass air flow sensor connector terminal identification-1991-94 SR20DE engine



Click image to see an enlarged view

Fig. Fig. 12: Inspect the heated wire for damage, dust or dirt build-up-1991-94 GA16DE engine



Click image to see an enlarged view

Fig. Fig. 13: Mass air flow sensor connector terminal identification-1995-96 GA16DE and SR20DE engines



Click image to see an enlarged view

Fig. Fig. 14: Mass air flow sensor parameter chart-1991-94 GA16DE engine



Click image to see an enlarged view

Fig. Fig. 15: Mass air flow sensor parameter chart-1991-94 SR20DE engine



Click image to see an enlarged view

Fig. Fig. 16: Mass air flow sensor parameter chart-1995-96 GA16DE engine



Click image to see an enlarged view

Fig. Fig. 17: Mass air flow sensor parameter chart-1995-96 SR20DE engine

  1. Pull back the mass air flow sensor harness protective cover, exposing the wire terminal ends.
  2.  
  3. Turn the ignition ON and start the engine. Allow the engine to fully warm up before continuing.
  4.  
  5. Turn the ignition OFF .
  6.  
  7. Connect a voltmeter between MAF sensor connector A and a known good engine ground on 1991-94 vehicles. For testing of 1995-95 vehicles, make connection between MAF terminal 1 and a known good engine ground.
  8.  
  9. Turn the ignition ON , but do not start the engine. The voltage reading should be less than 1.0 volt.
  10.  
  11. Start the engine and observe the voltmeter. Compare the readings to the specifications give on the MAF sensor parameter chart.
  12.  

If the voltages are out of range, perform the following checks before replacing the MAF sensor:

  1. Visually inspect the MAF sensor hot wire for dirt, dust, or damage. Clean if necessary. If okay, check wiring and power supply circuitry.
  2.  

REMOVAL & INSTALLATION



See Figures 18 and 19



Click image to see an enlarged view

Fig. Fig. 18: With the upper air cleaner housing cover off, unfasten the MAF sensor outer mounting bolts



Click image to see an enlarged view

Fig. Fig. 19: Some sensors may also be fastened from inside the air cleaner housing

1.6L (E16i and GA16i) Engines
  1. Remove the throttle valve switch for access.
  2.  
  3. Disconnect the MAF sensor electrical connector.
  4.  
  5. Remove the two retaining screws and slide the sensor from the throttle body, pulling it outward vertically.
  6.  


WARNING
Never touch the sensor portion of the MAF with your fingers.

To install:
  1. Coat the sensor-to-throttle body mating surface with silicone grease. This will provide proper heat dissipation.
  2.  


WARNING
Failure to apply silicone grease to the mating surface will cause premature sensor failure. Use extreme not to get the grease onto the sensor portion of the MAF.

  1. Install the sensor into the throttle body and secure with the retaining screws.
  2.  
  3. Connect the electrical connector.
  4.  

1.6L (CA16DE and GA16DE), 1.8L (CA18DE) and 2.0L (SR20DE) Engines

  1. Unplug the wire harness from the MAF sensor.
  2.  
  3. Disconnect the duct between the MAF and the intake manifold.
  4.  
  5. Remove the upper air cleaner housing and the MAF as an assembly.
  6.  
  7. Remove the retaining bolts which secure the MAF to the air cleaner.
  8.  
  9. Remove any gasket material from the mating surfaces.
  10.  

To install:
  1. Secure the MAF to the air cleaner, with a new gasket, using the retaining bolts.
  2.  
  3. Install the upper air cleaner housing.
  4.  
  5. Connect the duct to the intake valve from the MAF.
  6.  
  7. Plug the wire harness into the MAF.
  8.  

 
label.common.footer.alt.autozoneLogo