1. Remove the air filter. (See AIR FILTER REMOVAL/INSTALLATION [LF].)
2. Blow from port A and verify that there is airflow from port B.
If not as specified, replace the air filter.
3. Blow from port B and verify that there is airflow from port A.
If not as specified, replace the air filter. (See AIR FILTER REMOVAL/INSTALLATION [LF].)