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: Changing a Flat Tire
NOTE
If the following occurs while driving, it could indicate a flat tire.
Steering becomes difficult.
The vehicle begins to vibrate excessively.
The vehicle pulls in one direction.
If you have a flat tire, drive slowly to a level spot that is well off the road
and out of the way of tr ...
Mazda 6 Service Manual: No.3 passenger-side air bag cut-off indicator light does not illuminate
Diagnostic Procedure
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 malfunction. If there
is a problem, check to make sure connec ...