Removal (6-Cylinder - E46)
WARNING: This page does not describe the selected car, but rather 13 other vehicles, including the 1999 BMW Z3, 1999 BMW M3, 1999 BMW M Roadster, 1999 BMW M Coupe, and 1999 BMW 740iL. However, it is still accessible from the selected car via links, so may be relevant.
Remove air intake ducting. Disconnect electrical connection from retainer at cable duct. Remove bolt from knock sensor for cylinders No. 1-3, and bolt from knock sensor for cylinders No. 4-6. Remove knock sensors, located on side of engine block.