Air Flow Meter/Sensor: Description and Operation

- Uses a hot wire sensing element to measure the amount of air entering the engine. Air passing over the hot wires causes it to cool. This hot air is maintained at 200° C (392° F) above ambient temperature as measured by a constant cold wire.
- The current required to maintain the temperature of the hot wire is proportional to the air mass flow. 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 scheduling.