Checking Vacuum Valve In Cap
WARNING: This page is about a different car, the 2003 BMW X5, 2002 BMW X5, 2001 BMW X5, and 2000 BMW X5. However, it is still accessible from the selected car via links, so may be relevant.
Screw cap (1) onto special tool 17 0 007 and connect to vacuum hose of vacuum pump.
Feed vacuum pump with battery positive voltage.
Slowly apply partial vacuum to cap.
Compare opening pressure of vacuum valve.
Courtesy of BMW OF NORTH AMERICA, INC.