1. Remove the clamps and vacuum hose.
2. Apply both suction and pressure to the engine-side hose, and verify that air blows only toward that side.

Air bleeding
Brake pedal inspectionMazda 6 Service Manual: Technical data
ENGINE
LUBRICATION SYSTEM
Note
The maintenance intervals on scheduled maintenance table (See
SCHEDULED MAINTENANCE TABLE) can only be supported by the use of following
oils.
Recommended engine oil
COOLING SYSTEM
FUEL AND EMISSION CONTROL SYSTEMS
ENGINE ELECTRICAL SYSTEM
...
Mazda 6 Service Manual: No.6 windshield fogged
When performing an asterisked (*) troubleshooting inspection, shake the
wiring harness and connectors while doing the inspection to discover whether
poor contact points are the cause of any intermittent malfunctions. If there
is a problem, check to make sure connectors, terminals and wir ...