51 21 004 Adjusting Front Left Or Right Door Detent (Lock Wedge)
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2006 BMW M3, 2005 BMW M3, 2004 BMW M3, 2003 BMW M3, and 2002 BMW M3. However, it is still accessible from the selected car via links, so may be relevant.
Adjust left or right front door as necessary.