[myultimatemachine]

Hello everyone, I have a 2010 335i xdrive and I've been having nothing but problems with it for years. The current problem or so we think is the DME being faulty.

The circuit in question is the BSD line, I’ve been getting random active faults for a missing alternator, missing water pump and missing IBS sensor. All of these have been replaced with genuine new BMW parts and are all functioning perfectly. My mechanic and I tested the wires and found no issues, but no one seems to understand over there at BMW how to work their “scope” which is supposed to test the DME.

My only option given to me at this point is to have a tuning company clone my DME data and send me a used known working DME with my data on it but that’s $700 and I have spent over 20k in parts alone over the past 6 years on this car. That is because I built this to be an everything killer and is currently tuned with MHD. It also has a transmission tune (xHP) to make gear changes faster with higher line pressure to not grind gears.

My question to the community is how do I test the DME itself, what other tests can I do to verify the DME is bad? Any other tests at all before either spending money on a used DME or just selling it and being done. Is it possible that the MHD tune is causing these issues? I’m currently using V9 maps and the stage 2+ version. Has anyone else had a similar issue?

Any suggestions would be greatly appreciated. I have some friends who tell me to dump the car and sell it and some that tell me that I made it beautiful, and I should keep trying to fix it. I have hit a wall and do not know what to do.

Thank you in advance for your help.

[ptpending]

The BSD line is a CAN bus line, so it's requires a oscillograph to diagnose it, step by step. By disconnecting every unit in chain, checking signal and so on
when you find whos is guilty, you have to repair wiring or replace LIN transceiver in corresponding unit (or replace whole unit)

[myultimatemachine]

Originally Posted by ptpending

The BSD line is a CAN bus line, so it's requires a oscillograph to diagnose it, step by step. By disconnecting every unit in chain, checking signal and so on
when you find whos is guilty, you have to repair wiring or replace LIN transceiver in corresponding unit (or replace whole unit)

So basically what the dealership couldn't figure out how to do, test each component with the scope to find the problem. Are the LIN transceivers the components on the DME connecting to each part in this circuit?

[ptpending]

Originally Posted by myultimatemachine

So basically what the dealership couldn't figure out how to do, test each component with the scope to find the problem. Are the LIN transceivers the components on the DME connecting to each part in this circuit?

LIN transceivers are on all modules participating the bus
same with body CAN or PT-CAN bus