1. Remove the evaporative gas check valve (one-way).
2. Apply pressure to port A, and verify that there is no airflow.
3. Apply negative pressure to port A, and verify that there is air flow.

Charcoal canister inspection
Purge solenoid valve removal/installationMazda 6 Service Manual: Engine Exhaust (Carbon monoxide)
WARNING
Do not drive your vehicle if you smell exhaust gas inside the vehicle:
Engine exhaust gas is dangerous. This gas contains carbon monoxide (CO), which is
colorless, odorless, and poisonous. When inhaled, it can cause loss of consciousness
and death. If you smell exhaust gas inside the ...