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Air Flow Meter/Sensor: Description and Operation

MANIFOLD AIR FLOW (MAF) SENSOR




The Mass Air Flow sensor (MAF) is located on the rear of the engine attached to the throttle body, under the air cleaner housing. The MAF is constructed from plastic and also houses the Intake Air Temperature sensor (IAT).

The Mass Air Flow sensor (MAF) employs the following:
- (1) Temperature resistor
- (2) Sensor resistor
- (3) Hot film resistor
- (4) Electronics housing
- (5) MAF housing
- (6) Heating resistor

The MAF controls the temperature of the heating resistor (6) by means of a variable voltage so its temperature is 160° C (320° F) above the intake air temperature detected by the temperature resistor (1).

The temperature of the heating resistor (6) is detected by the sensor resistor (2). If a temperature change occurs as a result of an increased or reduced air flow, the PCM adapts the voltage at the heating resistor (6) until the temperature difference is again achieved.

This control voltage is used by the PCM as a measure for the metered air mass. The intake air temperature is detected by an additional Negative Temperature Coefficient (NTC) resistor.