Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

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Air Flow Meter/Sensor: Description and Operation

COMPONENT
Mass Air Flow (MAF) sensor

FUNCTION
Detects intake air mass. Outputs analog voltage signal to PCM. PCM controls operation as follows:
1. Required fuel injector pulse width
2. EPC
3. Shift/torque converter clutch scheduling

REMARKS
Uses a hot wire sending element to measure intake air mass. Hot wire is maintained at 2OO°C (392°F) above ambient temperature as measured by a constant cold wire. Air passing hot wire causes it to cool. The current required to maintain hot wire temperature is proportional to air mass flow. MAF then outputs signal to PCM.