Air Flow Meter/Sensor: Description and Operation
Air flow sensor (B2/1)
Intake Air Temperature Sensor (B2/1a)
Located in the air flow between the air filter and the turbocharger.
Acting against a return spring, intake air opens the air flow sensor plate to a specific angle. The position of the plate is measured by a potentiometer which converts the position into a voltage signal.
The intake air temperature is read by the temperature sensor (B2/1a) in the air flow sensor.