where is exactly in 2017 subaru legacy po073 MAF sensor
It's in the air duct from the air filter to the intake manifold. It's directly to the right of the air filter box mounted in the air duct. Remove the air filter box cover. Then remove the clamps holding the MAF in place. Look for debris on the delicate wires and temp sensor. Buy a can of MAF sensor aerosol spray and spray it onto the sensor and wires. Do NOT touch the wires with anything. Then clear the code and reinstall the MAF. See if the code comes back.