Check The Mass Air Flow Sensor Unit

Remove the mass air flow and intake air temperature sensor. Ref. to REMOVAL .
NOTE: Do not disconnect the connector.
Turn the ignition switch to ON. (Engine OFF)
Using the Subaru Select Monitor, read the intake air amount. Ref. to LIST .
Check the voltage changes when air is blown to the mass air flow sensor unit in arrow direction.
CAUTION: Be careful that no dust enter inside the unit when air is blown.

Fig 1: Mass Air Flow Sensor Unit Air Flow Direction
Courtesy of SUBARU OF AMERICA, INC.
After inspection, install the related parts in the reverse order of removal.