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.
Mazda 6 Service Manual: Dual proportioning valve replacement (without abs)
1. Remove in the order indicated in the table.
2. Install in the reverse order of removal.
Dual Proportioning Valve Installation Note
Install the dual proportioning valve so that the R mark faces the left side
of the vehicle.
...
Mazda 6 Service Manual: Operational Range
The system operates only when the driver is in the vehicle or within operational
range while the key is being carried.
Starting the Engine
NOTE
Starting the engine may be possible even if the key is outside of the
vehicle and extremely close to a door and window, however, always start the ...