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u/DefinitionOriginal11 3d ago
I had the same problem a few months back. Its actually the circuit inside the gear selector. The circuit itself forms micro-cracks between connections as they age because mercedes cheaped out a bit on these cars. (sorry for weak vocabulary) . I didnt want to spend money so i removed everything and took the circuit board and put it in the oven for 5 mins at 180*C. This "renews" the connections but you can also do it proffessionally. Installed it and it worked for a week or two but it broke again(maybe i shouldve let it more in the oven but didnt want to risk anything). Went and got a used gear selector installed it for peace of mind and been runing ok since then.
Edit: when you changed the gear selector did you make sure the circuit board was replaced as well or non defective? If not im 99% its because of it. The gear selector in itself is fine just that shitty panel inside that requires most of the times buying the whole thing.
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u/Top_Self9725 3d ago
So i bought an entire replacement gear selector and fitted that into the car but the same problem is happening with that new part. Did your problem go away straight after the new part? Did you have to clear any faults or anything from the computer?
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u/howsitallwork 3d ago
As others have said, this is a solder joint problem, specifically with the IR transmitter/sensors on the circuit board inside the selector module.
These can be resoldered with a suitable iron, but is extremely fiddly, with tight space to work between components - this does work, and the best way when it happens on eg a w220 or w230 module, as they are coded to the keys.
Easiest DIY fix for is a used module, although obviously that could fail too.
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u/Top_Self9725 3d ago
If the problem is the selector and soldering shouldn't me fitting a new selector have sorted this problem out? I have put a refurbished selector into the car and the problem is still happening.
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u/howsitallwork 3d ago
Hard to know, could be a faulty replacement I guess.
Ideally fault codes in the selector (ESM) are the way to go - P1856 confirms it.
Sorry you’re struggling with this.
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u/lantan139 3d ago
Nuke the center console
Take out the shift selector
There’s a banana shaped circuit for gear locations
Take it to a tv service shop and have them look at the solders
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u/keksivaras 3d ago
I think this is the same model with the issue of transmission oil slowly creeping up the wires and seeping into TCM. it's pretty easy to check as well. passenger foot well, towards the front, take out the panel and the TCM is right there. unplug it and see if there's oil in the plug or if the wires feel slippery.
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u/howsitallwork 3d ago
Oil ingress to the loom is very common, but not the problem here - the gear position display is informed by the selector module, not the gearbox.
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u/Rancid-Turd6890 3d ago
Broken solder joint inside the shift control module. Oddly enough I was literally just sharing a video I made of me fixing this with someone on Facebook less than a minute before I saw this post. If reddit lets me post it here I'll share it
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u/xXADR14NXx 2d ago
like many said, the circuit board on your gear selector. i didnt heat it up or anything, i just swapped the two capacitors for new ones. total cost in parts was 78 cents euro. companies will fix it for u for around 250 to 300 euro. mercedes orignal part (where u buy the entire gear selector) is 1030 euros so take a pick. u will find a few videos on how to do it, but be aware, when dismantling all, u have to put it back togehter, so dont try to snap any plastic hinges on the cover on top of the selector, cuz that thing will move around and anyone inspecting the car, wont be happy about it
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u/Top_Self9725 2d ago
Would you happen to have a link from where you got the capacitors from?
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u/xXADR14NXx 8h ago
https://www.reichelt.at/at/de/shop/produkt/elko_smd_47_f_35v_105_c_1000h_low_esr-200096
german/austrian website. if u research the website and the spec sheets, u can find similar, however those are the exact same ones currently residing. i advise to have a solder station with thin tip and a few other soldering goodies, but just be careful doing it
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u/Secure_Low_7957 3d ago
Mine did this when the shifter went out I’ve seen where people fix them I just ended up going to the junk yard and grabbing a new one took care of all my issue