Removal & Installation (3-Series)
WARNING: This page does not describe the selected car, but rather 12 other vehicles, including the 1997 BMW Z3, 1997 BMW M3, 1997 BMW 840Ci, 1997 BMW 740iL, and 1997 BMW 740i. However, it is still accessible from the selected car via links, so may be relevant.
ECU is located behind cover on firewall in right rear of engine compartment. On 4-cylinder vehicles, remove battery. On all vehicles, remove 4 ECU cover screws. See Fig 1. Unlock electrical connector retainer. Disconnect electrical connector. Slide out ECU. See Fig 2. To install, reverse removal procedure.