SCM Replacement
I have a LIN bus communication error permanently on my SCM, so I think it is time to replace it.
Could anyone point me to where this thing lives?
Resetting the fault (9001 I believe) bring back the code immediately: 'stored and current' condition.
I verified my clock spring, the transmission is receiving the shift button signals but the SCM doesn't see any values coming through.

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Simply resolder the loose connector pins carefully left out to get your attention. The bonus is EIS nearby ... the result is a mind boggling engine/tranny improvements (Look at link in my signature).
Last edited by CaliBenzDriver; May 1, 2023 at 02:50 PM.




SCM is built with pressed pins circuit boards that have a limited reliability. Fortunately its easy to work with once you have the wheel removed (center your wheel at 0°Ref. to help reassembly or better follow WIS procedures).
> PRACTICALLY:
Proceed by layers or just do it all right at once
SCM is built like an interconnected sandwich stack of modules, connectors, boards.
- Either you spend time splitting-hair about testing where your issue is located then order a collection of parts...
-OR you solder all loose pins then test all works well afterwards.
- INCENTIVE:
SCM "wheel position sensor" is a super busy module for these cars with smart braking functions.
Read that...:
Once I've fixed my low mileage SCM & EIS, my tranny started to shift remarkably fast... "No faults" go figure!
So yeah, a working horn is good but this failure is an opportunity to do a lot of good with a little spare time.
Steering column top has a dry ball bearing that's waiting for lubricant to make your steering wheel velvet smooth.
This small problem can be treated as an opportunity for vast improvements! A quick cheap job can be good enough.
Last edited by CaliBenzDriver; May 1, 2023 at 02:50 PM.




They should be really positive guide, right?
Let us know.
Last edited by CaliBenzDriver; May 1, 2023 at 03:56 PM.




one layer of SCM with dry bearing race and loose pins (w212)
Have a look at your column for positive opportunities to improve many issues at once.
Follow your horn connection to clock-spring to SCM sandwich stack... post pics of these connections if you will
Last edited by CaliBenzDriver; May 1, 2023 at 04:01 PM.




Are you saying if I remove this out of the cover I will see what your picture is showing? Or will I have it dismantle it more to see what you are showing??
Mine looks a lot different than what you are posting. I'm driving an E55, is yours a different model of car?
You can test signals from horn button using a scanner with live car data.... then closely inspect SCM.
N80 is the hub module
You can concentrate on N80 known as SCM where all options connect to.
Last edited by CaliBenzDriver; May 1, 2023 at 06:34 PM.




SCM male Pins to car female connector
These pins are the interface point of SCM to car. Peal off plastics assemblies to reveal bare circuit board if you are able to.
Free repairs for the braves !




I like evidence... let's see what nice things you got in that E55
we can guide you from there 👍




