SMFA and SMBF are terms used by BMW to refer to driver's seat module and passenger seat module. Driver's seat module (SMFA) and passenger seat module (SMBF) activates the seat memory and the mirror memory. Another function of these modules is the adjustment of the front seats controlled by Hall sensors.
When your BMW Seat module fails you may notice symptoms such as not being able to adjust the seats, side mirrors or store seat position in memory.
If you are experiencing problems with your BMW seats first check the seat fuses, relay and even the seat motor. If you are still experiencing problems with the seats, the next step is to read fault codes from the Seat module.
What you will need
For this step, you will need a diagnostic scanner that is capable of reading fault codes from BMW Seat module.
These are general instructions and may vary depending on the diagnostic scanner model that you use to diagnose BMWs.
Plug in the OBD-II scanner into the diagnostic port under the dashboard.
Turn on the ignition, don't start the engine.
Turn on the scanner and select your BMW chassis. Next, Select Control Units menu.
Select Seat Module.
Once you enter the Seat module, you will be able to do the following.
Read Codes from Seat Module
Clear Codes from Seat Module
Perform Adaptations, Activations, Tests
If any code is showing PRESENT status the problem needs to be fixed before the code can be cleared. If you can not communicate with your BMW seat module, your module is defective or your vehicle is not equipped with a seat module.
If the vehicle is not equipped with "Seat memory" option, that vehicle will not have a seat module nor Hall sensors fitted. In such cases, when you try to access the seat module, you will get no communication error.
In these BMWs, the seat is adjusted until it reaches an end position. When you move the seat all the way forward or backward, junction box electronics (JBE) recognizes the increased power draw at the end of the rail. If excessive power draw is present, the JBE will switch the seat motor off.