Originally Posted by rodybmw

Do you get the same message as in the picture below? I got that in my 545 two winters ago and again a couple of weeks ago. It is common on E60's/E63's and 90% of the time it just means your Power Steering Fluid is slightly low, so when the weather gets cooler and the car is left off overnight (or a few hours) you get that message when you first start.......this is especially true when the car is parked on an incline. Once you get the car on a flat surface and it warms up slightly, if you shut it off and re-start it will go away.

Adding Power Steering Fluid to the appropriate level makes the message go away. Check the level and see if it is slightly low, and if you add the fluid yourself make sure you get the right type (it says on the P.S. fluid reservoir cap). My local generic auto parts stores (Pep Boys, Kragen) didn't have it so I had to get it from a store that sold European auto parts. If I remember correctly it was a CHF12 or something like that.

There was no question in mine and other E60 owners' cases that the P.S. Fluid level was truly marginally low and filling it to the correct lever made the message go away, but the question is why was it low to begin with. There doesn't seem to be a leak anywhere. I am planning on having the dealer do a thorough check for leaks in a couple of weeks to make sure it is fine.