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: Electrical parts
Battery cable
Before disconnecting connectors or removing electrical parts, disconnect
the negative battery cable.
Wiring Harness
To remove the wiring harness from the clip in the
engine room, pry up the hook of the clip using a
flathead screwdriver.
...
Mazda 6 Service Manual: Vehicle speedometer sensor (vss) inspection
Visual Inspection
1. Remove the VSS. (See VEHICLE SPEEDOMETER SENSOR (VSS)
REMOVAL/INSTALLATION.)
2. Make sure that the sensor is free of any metallic shavings or particles.
If any are found on the sensor, clean them off.
3. Install the VSS. (See VEHICLE SPEEDOMETER SENSOR (VSS)
REMOVAL ...