Toyota Camry 1983-1996 Repair Guide

Mass Airflow Meter/Sensor

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OPERATION



See Figure 1

The Mass Air Flow Meter (MAF) contains a spring-loaded measuring plate or cone. The plate/cone is connected to a pointemeter which controls the signal to the ECM. In this way, the control unit is advised of intake air volume and can control injector duration and ignition advance accordingly. All engines except the 5S-FE engine uses an air flow meter. The 5S-FE engines uses a Manifold Air Pressure (MAP) sensor.



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Fig. Fig. 1: Cutaway view of a common MAF meter assembly

TESTING



See Figures 2 thru 11

  1. Disconnect the wiring from the air flow meter.
  2.  
  3. Using an ohmmeter, measure the resistance between each terminal as shown in the charts.
  4.  
  5. If the resistance is not as specified, replace the air flow meter.
  6.  



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Fig. Fig. 2: Air flow meter terminal identification-2S-ELC engine



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Fig. Fig. 3: Air flow meter terminal identification-3S-FE and 2VZ-FE engines



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Fig. Fig. 4: Test the resistance of terminals E2 (1) and THA (2) of the MAF sensor-1MZ-FE engine



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Fig. Fig. 5: Air flow meter test values-2S-ELC engine



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Fig. Fig. 6: Air flow meter test values-1MZ-FE engine



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Fig. Fig. 7: Air flow meter test values-3S-FE and 2VZ-FE engines



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Fig. Fig. 8: Air flow meter test values-3VZ-FE engine

  1. Inspect the meter operation. Connect the MAF meter wiring.
    1. On 1994 models, connect a voltmeter to the positive (+) test probe to the VG and the negative (-) test probe to terminal E21.
    2.  
    3. On 1995-96 models, connect a voltmeter to the positive (+) test probe to the VG and the negative (-) test probe to terminal VG-.
    4.  

  2.  
  3. Blow air into the meter and check that the voltage fluctuates.
  4.  
  5. If the operation is not as specified, replace the MAF meter.
  6.  



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Fig. Fig. 9: Attach the test probe terminals to the E21 (first pin) and VG (fourth pin) from the left of the MAF meter-1994 1MZ-FE



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Fig. Fig. 10: Attach the test probe terminals to the VG- (first pin) and VG (fourth pin) from the left of the MAF meter-1995-96 1MZ-FE



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Fig. Fig. 11: Blow air into the MAF meter and make sure the voltage fluctuates

REMOVAL & INSTALLATION



See Figures 12 thru 17

  1. Disconnect the air flow meter wiring harness from the unit.
  2.  
  3. Remove the air cleaner hose on the engine. First the PCV valve hose may need to be disconnected.
  4.  
  5. Loosen the air cleaner hose clamps and pull the unit off the engine.
  6.  
  7. Remove the MAF meter retaining bolts.
  8.  
  9. Lift the meter unit off the engine.
  10.  
  11. Installation is the reverse order of removal. Tighten the meter screws to 61 inch lbs. (7 Nm).
  12.  



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Fig. Fig. 12: Separate the harness connector from the Mass Air Flow (MAF) sensor



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Fig. Fig. 13: Disconnect the PCV hose before removing the MAF sensor



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Fig. Fig. 14: Loosen the air cleaner hose clamps



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Fig. Fig. 15: Now the air hose can be pulled off the MAF and throttle body



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Fig. Fig. 16: Unbolt the MAF from the engine



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Fig. Fig. 17: Pull the Mass Air Flow (MAF) sensor off the engine

 
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