Mass Air Flow (MAF) & Intake Air Temperature (IAT) Sensor Inspection
Mass Air Flow (MAF) & Intake Air Temperature (IAT) Sensor InspectionIAT sensor inspection
CAUTION:
- When servicing MAF & IAT sensor, be sure to observe the following items.
- Do not disassemble MAF & IAT sensor.
- Do not expose MAF & IAT sensor to any shock. If it has been dropped, it should be replaced.
- Do not clean MAF & IAT sensor.
- Do not blow compressed air by using air gun or the like.
- Do not put finger or any other object into MAF & IAT sensor.
- Do not heat MAF & IAT sensor more than 100 degree C (212 degree F).Otherwise, MAF & IAT sensor will be damaged.
1. Remove MAF & IAT sensor.
2. Check sensor O-ring (1) for damage and deterioration. Replace as necessary.
3. Measure resistance between sensor terminals while blowing hot air to temperature sensing part (2) of MAF & IAT sensor (3) using hot air drier (4).
If faulty condition is found, replace MAF & IAT sensor.
Intake air temperature sensor resistance
-20 °C (- 4 °F): 12.6 - 15.1 kohms
20 °C (68 °F): 2.29 - 2.55 kohms
80 °C (176 °F): 0.312 - 0.370 kohms
MAF sensor inspection
1. Remove MAF & IAT sensor.
2. Connect three new 1.5 V batteries in series and check that total voltage is 4.5 - 5.0 V
3. Connect 12 V battery (1), 1.5 V batteries (2) and 1.2 kohms resister (3) to MAF sensor as shown in figure.
4. Connect oscilloscope (5) or multimeter (4) to MAF sensor as shown in figure.
5. Check that waveform or frequency varies depending on amount of blowing air to air intake vent (6.using oscilloscope or frequency range of multimeter.
If faulty condition is found, replace MAF & IAT sensor.
MAF sensor waveform (reference)
Calm:
Blowing:
