How Mass Air Flow Sensors Work

Step by step guide on how an automotive mass air flow sensor (MAF) works.

Step 1 - The mass air flow sensor is designed to monitor the volume of air passing into the engine at any giving time (located in the intake tube connected to the throttle body) this information is then transmitted to the computer for calculations while helping adjust fuel injector input and ignition timing settings.

Mass Air Flow Sensor (Appearance will vary.)

Step 2 - All maf sensors include an electrical connector which is used to transfer data to the computer.

Mass Air Flow Electrical Connector

Step 3 - A hot wire is used to detect air flow by measuring the resistance change as varying amounts of air are passed over it.

Mass Air Flow Hot Wire

Step 4 - Sensor wiring diagrams are used to help troubleshoot electrical problems.

Wiring Diagram

Helpful Information

A mass air flow sensor can become inaccurate after large amounts of air (high mileage) has passed over the hot wire and must be cleaned before normal operation will return. These sensors are delicate and are prone to failure, fortunately replacement is simple in most cases. Engine performance issues involving this sensor include, hesitation, low power and poor mileage.