E46 Stepper Motor Controllers: Layout
WARNING: This page does not describe the selected car, but rather 37 other vehicles, including the 2006 BMW 330Ci, 2006 BMW 325Ci, 2005 BMW M3, 2005 BMW 330xi, and 2005 BMW 330i. However, it is still accessible from the selected car via links, so may be relevant.
The block diagram shows the stepper motor controller and its connections.
To differentiate between the two headlights (left and right), pin 12 of the stepper motor controller for the LEFT-HAND headlight must be connected to earth. The SMC must be coded accordingly (either by the headlight manufacturer at the end of the production line or in the workshop after replacement).
STEPPER MOTOR CONTROLLER BLOCK DIAGRAM LEGEND
| Key | Explanation | Key | Explanation |
|---|---|---|---|
| 1 | AHL control unit | 2 | Supply voltage |
| 3 | Earth | 4 | Stepper motor controller (SMC) |
| 5 | Stepper motor for automatic headlight-range adjustment | 6 | Stepper motor for adaptive headlights |
| 7 | BMW diagnostic system with DISplus | 8 | Coding pin for right or left |
| 9 | Zero-position sensor | LIN bus | Local Interconnect Network, local bus between AHL control unit and SMC |