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BSD Protocol input

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Some BMW vehicles uses a BSD protocol to communicate with some modules, like oil level sensors (also measuring oil temperature), alternator control and the Waterpump.

Our special BSD board is REQUIRED for this functionality.



Wiring information

DIN 3 (GPO 7) needs to be wired to the BSD board DIN activated as BMW BSD bus 1 Input.

Any available GPO (GND) output needs to be wired to BSD board GPO and activated as BMW BSD Bus 1 Output.

Switched +12V.

Engine GND.

BSD to the BSD peripheral wire.

NOTE: always use the same GND and +12V source on the BSD board AND the BSD module (s).

Note: a Single BSD is only needed, even if you are using 2 or more BSD modules, just connect them to the BSD board.




1. Our special BSD board (product ID 2134) is required to communicate with these BMW peripherals.



2. Wire the BSD peripheral BSD output wire to the DIN 3 of your MaxxECU and activate input as BMW BSD bus 1 Input.

Note: ONLY DIN3 can be used, DIN3 is actually the GPO7 Used as digital input 3.



3. Wire the BSD board GPO to ANY MaxxECU GPO (GND) and activate the output as BMW BSD bus 1 Output.



4. Control settings is now visible under Inputs --> BSD Protocol Input 1 in MTune.



5. A few more RealTime Data values are now available in the system.



Oil level sender


oil sensor communication

Enable the oil level sender communication.


Note: Oil temperature is also transmitted from the oil level sender, which is displayed in the RealTime Data value OIL TEMPERATURE.


Wiring BMW oil level sender:

Pin1 - BSD on circuit board.

Pin2 - GND on circuit board.

Pin3 - 12V on circuit board.


Confirmed BMW oil level senders

BMW 7567723





Alternator communication

Enable the alternator communication.


target voltage

Specifies the alternator target voltage.





Waterpump communication

Enable the waterpump communication. controlled under the normal waterpump system (Outputs --> Waterpump control).


RT-values for Current, Speed and Error flags are available.


Confirmed BMW waterpumps

VDO A2C59514607 (generic number).

A2C53326031 (part number)

A3C0260610000 (part number)

11519455978 (BMW OE number).

11517632426 (BMW OE number).


BSD water pump wiring

E9X N54 from 9/2007



BMW OE water pump connector, part nr 75390719, kostal: 10098866





+12V ignition signal




+12V power supply, fused 40A






Note: The water pump will eventually go into a sleep/power saving mode without an Ignition signal (1). If there is no BSD signal when the ignition status wire is powered, the water pump will go into a fail-safe mode (full speed).