E 450 V8-5.4L (2009)
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Air Flow Meter/Sensor: Description and Operation
Engine Control Components
Engine Control Components
Mass Air Flow (MAF) Sensor
The MAF sensor uses a hot wire sensing element to measure the amount of air entering the engine. Air passing over the hot wire causes it to cool. This
hot wire is maintained at 200°C (392°F) above the ambient temperature as measured by a constant cold wire. The current required to maintain the
temperature of the hot wire is proportional to the mass air flow. The MAF sensor then outputs an analog voltage signal to the PCM proportional to the
intake air mass. The PCM calculates the required fuel injector pulse width in order to provide the desired air/fuel ratio. This input is also used in
determining transmission electronic pressure control (EPC), shift and torque converter clutch (TCC) scheduling.
The MAF sensor is located between the air cleaner and the throttle body or inside the air cleaner assembly. Most MAF sensors have integrated bypass
technology with an integrated IAT sensor. The hot wire electronic sensing element must be replaced as an assembly. Replacing only the element may
change the air flow calibration.
Diagram of Air Flow Through Throttle Body Contacting MAF Sensor Hot and Cold Wire (and IAT Sensor Wire Where Applicable) Terminals
Diagram of Air Flow Through Throttle Body Contacting MAF Sensor Hot and Cold Wire (and IAT Sensor Wire Where Applicable)
Terminals.
Typical Mass Air Flow (MAF) Sensor
Typical Mass Air Flow (MAF) Sensor