Checking fluid level
WARNING: This page is about a different car, the 2003 BMW 525i, 2002 BMW 525i, and 2001 BMW 525i. However, it is still accessible from the selected car via links, so may be relevant.
Carry out fluid level check with engine off at expansion tank of power steering/ride-height control; if necessary, top up hydraulic fluid to Max. marking (1). See Fig 1.
NOTE:
If the fluid level has dropped to the Min. marking (2), you must check the power steering and ride-height control for leaks and issue a separate invoice for this work. It is not enough merely to top up the fluid.