This question might be too technical for this forum, but I'll give it a go. I have a 2012 BMW R1200R motorcycle with CAN-BUS. I'd like to make an Arduino interface to the connector on the bike, but I don't know the pin definitions...

Do anyone know the pin definitions or how to figure out what they are?


Pin #.Wire color.Ohms with disconnected battery.Voltage with key off.Voltage with key on  
1     Green/Blue  3.2 ohms                       0 V                   12.25 V  
2     Red         2.2 KOhms                      12.9 V                12.32 V  
3     Brown       0.4 Ohms                       0 V                   0 V
4     Brown/Black 16 Ohms to 12.4 Ohms           ~0.003 V              11.2 V

Pin 2: Two +12V lines probably means this is a battery pin?

Pin 3: Possible ground pin with two 0 volt pins?

Update 2:

The OBD Wiki shows that for these pins it must be one of three protocols: ISO 9141-2, ISO 14230 or ISO 15765. I don't have all the chips needed to test 9141 or 14230, but I'll have them and another update within two weeks.

R1200 Diagnostic Plug

  • Have you asked over on advrider.com? There may be some GS eggheads that could help.
    – mac
    Oct 25, 2012 at 14:39
  • 1
    Wikipedia suggests that it isn't a standardised pinout, so you'll have to find a BMW-specific pinout for it unfortunately...
    – Nick C
    Oct 25, 2012 at 14:59
  • mac - Thanks, I'll give them a shot.Nick - Yeah, I figure it's going to be harder than it should be. I was hoping to just bust out an O-scope and stumble upon the right one. Oct 25, 2012 at 20:14
  • if you find anything out, be sure to post your own answer!
    – mac
    Oct 25, 2012 at 20:31
  • Update: So, I blew up my first board by just plugging it into some wires. I now have a new board and will test my code on my car's system which is well documented. Dec 12, 2012 at 0:05

1 Answer 1


I was looking for the similar thing and stumbled on a page which describes the protocol for the 650gs. I haven't managed to try it out yet but it seems promising. http://www.f650gs.crossroadz.com.au/Diagnostics.html

Topic is discussed here as well: http://f650.com/forum/showthread.php?25550-Diagnostic-plug-pinout-does-anyone-have-it

Plese let my know how are you doing with your project. I have a similar arduino-gs-related thing in mind :)


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