Hello,

I have a common TCU failure issue on my E61 530D LCI 57 Plate.
I have lost voice control, BT, SOS assist. All which is part of the TCU I believe. Ever since I bought the car (2 months ago).

NCS Expert is not able to communicate to Module TCUM and INPA shows errors in the MOST BUS.
For giggles, I swapped my TCU for another known working one, and still not able to communicate to that module either.

So, I am now going to try and hunt down which module in the MOST loop is cranky. Anything is better then taking it to a stealer at this stage ;(no money).

Thing is, Im not entirely sure where to start on the MOST apart from the TCU. I have know idea what is next in the loop.

When I disconnect the Optical cable from the TCU, I can see light eliminating from inside the TCU ok, but no light coming form the optical cable. Should I be able to see a light on the cable when I pull it out?

The strange thing is, everything else works on the car (that I'm aware of, just not the TCU.

Any guidance would be wonderful please.

 

First, try to see what else is on the MOST, by what you are saying it could be the one before the TCU, maybe CD changer?

Do you have any issues with Idrive or CCC? Switching of or going black?

 

MOST BUS issue effecting TCU - E60/E61 2004-2010 - BMW 5 Series Owners Board

Due to missing loop cap on ops cable