Every BMW E34 uses a service reminder system that illuminates a message on the instrument panel when the computer determines regular maintenance is needed. After you've performed the maintenance, though, sometimes the light fails to reset. In this case you'll need to reset it manually so the computer can accurately track the interval until the next service reminder.
Turn the ignition off. Open the hood.
Twist open the cap of the data link connecter, located directly in front of the engine.
Bend the paper clip into a "U" shape. Insert one end of the paper clip into port #7. Insert the other end into port #19. Each port has a small number next to it.
Turn the ignition switch to "ON" without starting the engine.
Remove the paper clip from both ports after the ignition has been on for five seconds.
Replace the cap to the data link connector.
Turn the ignition off.
