Air Flow Meter/Sensor: Testing and Inspection

Fig. 8 Air Flow Sensor Power Supply Testing:

Fig. 9 Air Flow Sensor Electrical Operation Testing:

1. Check power supply as follows:
a. Disconnect electrical connector from air flow sensor.
b. Connect voltmeter between pin No. 2 of connector, Fig. 8, and ground.
c. Engage starter.
d. Correct voltage reading is above 9 volts.
2. Check ground as follows:
a. Connect ohmmeter between pin No. 3 and ground.
b. Correct resistance is less than 1 ohm.
3. Check mechanical operation as follows:
a. Remove air cleaner cover and air filter element.
b. Depress sensor flap. Opening motion must be smooth and without drag.
c. Ensure no friction exists between sensor flap and housing.
4. Check electrical operation as follows:
a. Connect ohmmeter between pins 5 and 8, Fig. 9. Correct resistance value is 340-450 ohms.
b. Connect ohmmeter between pins 8 and 9. Correct resistance value is 160-300 ohms.
c. Connect ohmmeter between pins 5 and 7. Resistance reading will vary depending on the position of the flap within the airflow sensor.
d. Vary the position of the flap with a screwdriver. Correct resistance reading is 60-1000 ohms.