BSD faults

Michael from Commack Technical Support Specialist Posted   Latest   Edited  
Tech Tip

BSD in N52, N54 and N55 engines.

BSD ( Bit Serial Data line)

The bit-serial data interface is a single-wire data bus with a data transfer rate of 1.2 kBit/s.

The following components are connected across the bit-serial data interface with the DME control unit:

  • Alternator (varies according to version)
  • Intelligent battery sensor (depending on model series)
  • Electric coolant pump (depending on variant)
  • Oil condition sensor (depending on variant)

DME is master controller 

The first check: ALT, needs to be OEM 

see attachments for various known good scope images from various scopes. 


Steven from Spokane



Hello Michael,

I have to mention that the picture you attached does not look like a known good pattern. It may be that the scope could not capture the fast signal. I found a good pattern here

That image is from this web page picoauto​.​com/library/case-s…


Eric from Peoria


Mobile Technician

Hello Steven,

The snap on capture is flawed not due to scope speed/resolution, it is not setup up correctly- timebase is incorrect. It has WAY too much time on the screen. This causes the scope to alias or "guess" where it should "connect the dots" on the screen

This is a common issue with SO users. The scope should be setup somewhere a 50 ms time sweep which is the equivalent of 5ms per division.

The buffer would fill and then the capture would be stopped and zoom out and then zoomed in.


Steven from Spokane



You got it. Thanks Eric. ☺️


Eric from Commack


Technical Support Specialist


Are you authorized to reuse that material without permission from Pico? Is that copyrighted material?


Steven from Spokane



If I need to remove the link to the image, I will. The other link is just to their website that is publically viewable by anyone. It's not a private webpage.


Scott from Claremont



I don’t see an issue here Steven, you simply linked to an image on a public webpage which supported embedding.


Steven from Spokane



Thanks for checking 👍