Deflating all air springs or reservoirs

This function attempts to depressurize the system by opening outlet valves for a certain time.
When the time has expired, the function assumes that the system is depressurized.
It is always the mechanic's responsibility to check that the system is without pressure.
That the function has been run successfully does not necessarily mean that the system is without pressure.
Note:
When the function is done, there will always be some overpressure in the system.
When removing components, make sure that all parts are loosened carefully and slowly to release any air.
When the work is done, the system must be refilled using the associated function before the car is driven.
Preconditions for the test:
Procedure: