Did you have the airbag off? If so, does the "Y" harness that connects to both shift buttons have a 2-pin connector or 3-pin connector (at the end that does NOT plug into a shift button)? If it has a 2-pin connector, then your car has the early (analog) configuration AND disconnecting ANY wire connected to the shift buttons will open the circuit and make the car ALWAYS think you are holding the upshift button.

Chris

I did not check the wires but I have replaced my steering wheel with one with wires intact, i want to say it was 3 wires like you said for an 05. With my scanner I see the steering column module reads my paddle shifts correctly, and I have replaced my transmission module with still no luck. I see the steering module feeds into the CAN-C and then the transmission module. I want to test voltages and continuity but I cannot find which connector is which online, and I am unsure if disconnecting wires and hoping for the best is the next course of action. What should I do to test the CAN? I really am stuck here. No matter what the transmission module thinks someone is mashing that upshift button from the steering wheel (not the floor shifter, i checked).

what was changed on the car since the last time the steering wheel shift buttons worked properly?

Since I bought the car I have had the problem. I've replaced the steering wheel and the transmission module. I've also replaced the transmission, but the issue was before and after the transmission. I got the car about 10k miles ago

IF you are reading the steering wheel shift buttons as working properly when scanning the SCM ... and you are reading the touchshift (both down AND up) as working properly when you are scanning the shifter. Then I would question if you have the correct TCU (is it for a 2005 or later?) . IF there were a wiring issue between the SCM and the can or the tcu and the can, I would think you would be getting communication error codes.

I have seen this one time where the engine oil level sensor is bad. For whatever reason it is tied in ???? Faulty response from paddles...could be wrong ?

interesting ...
When you say that it was "bad" ... was it just reading wrong (like too low ... when the level was fine)?

Unfortunately I have not only checked the TCU but replaced it just to be safe. Same result

I am curious about this too. I mean don't get me wrong at this point I'll try nearly anything, but are there any signs it's bad? Or is it kinda a shot in the dark? I think I've read the same thing somewhere else. Wiring diagrams don't show it's related but who knows at this point

No they just did not work or work correctly. Do a search and it should come up as to the issue and fix but I know for whatever reason the circut runs through the oil level sensor...
You know....Mercedes engineering !!LOL

I had read that you had replaced it. I was just curious if you are certain what the replacement was from.

My bad, it was from another 2005 e55. I double checked the part numbers matched as well. I went on some mboemparts thing and verified that it was the correct part number too. I ordered the oil level sensor just to give it a shot either way.

Update, replaced oil level sensor with a brand new OEM one. Still the same issue... Any ideas?

I have the can bus C exposed, and I have the wiring diagram, but there is no way that I know to know which cable is the one im looking for to the TCU. Any help on how to identify it? Thanks for any help

This thread is the closet i can find to my issue so im bringing it back.

My 2003 S55 AMG paddle shifters have never worked since i got the car. The floor shifter works with manual mode as designed however nothing happens at all with either paddle shifter.

I found distronic/voice command selector in my trunk labeled for an 02 s600 that someone either planned to install for some reason. Maybe in an attempt to fix random distronic errors. The voice command stalk on my wheel right now is not on and was located in the trunk so maybe they just planned to fix that. Is that part in anyway connected to the paddles? Part is same as linked https://www.ebay.com/itm/15221643729...mis&media=COPY

I also have no idea what may have been replaced in the past. Would the shift selector maybe be an issue? Why do those need to be replaced/repaired?

Just kind of wondering where to start looking. Doesnt seem like an issue with paddle wiring because the manual mode works fine with the floor selector unlike previous posters.

Yes, your 2003 S55 does have the same steering wheel shift button (electronic) configuration as the 2003-2004 E55 & CLK55 (along with the 2003-2006 SL55/65, CL55/65, S55/65 and SLR McLaren), so it does make sense to pose this question here. You have done a great job of gathering the essential clues to your issue and have already guessed the most likely correct answer (floor shifter was replaced with one that was not coded for AMG shift buttons is more than likely what has happened).

Given the configuration of this early version of AMG shift buttons, the fact that your touch shifter functions WHILE your steering wheel shift buttons do not .... pretty much rules out a problem with the shift buttons and/or wiring (if your shift buttons were NOT plugged in OR there was a break anywhere in the wiring, the car would interpret that as you pressing the "UP" shift button ... thereby disabling the floor shifter touch-shift function).

On these "early amg shift buttons config" cars, the floor shifter is programed for steering wheel shift buttons while it is still a virgin. Once it has been driven some, this can not be changed. So, your shifter was likely replaced with a used shifter from a non-amg car OR, it was replaced with a new shifter, BUT the installer failed to set it for AMG shift buttons.

Hope that helps.... if you have more questions feel free to send me a note a Latemodel21@yahoo.com

Chris

Well that is pretty rough news. Seems the only way to fix it to use paddles would be spending thousands on a new shifter from the dealer and making sure its programmed correctly? Wild that the feature cannot be programmed into a used unit.

My understanding is that the window of opportunity on setting this option in the shifter is small (and not something that can be addressed later with a star tester, etc). However, you might want to double check with a Mercedes super-tech to see if this can be corrected with SCN coding (DO let us know if this works out).

Since the floor shifter is a "theft related" part (tied to "drive authorization") a swap with a used part wont work (unless you change out the ECU, EIS and possibly CGW and more .... at the same time), so a new shifter may be the only way to solve this (make SURE that they know the new unit must be coded for steering wheel shift buttons if you go this way).

Best of luck,
Chris

Hi

I have a CLS55 2005. It shift to higher gear when I try to shift to lower gear. The high shift works.

I quess the switches are working. The earlier owner has made a short circuit to high hear PCB instead of the 100 ohm resistor. The low side PCB do not have 100 Ohm resistor at all (actually it seems it havent newer even had the resistor soldered).

As far I understood from previous posts that is how it should work if low side PCB do not have a resistor. Did I understood correctly?

How do I know I have a correct PCB’s there as I think I do not have its own steering wheel? Have you found the schematics for the both PCB’s? I could just put 100 Ohm resistors to both sides but I wonder if I break something. I would like to have also shift to low working properly.

Parhaps the earlier owner has wanted to shift to higher gear using both buttons?

Br,

CLS55

IF this is a CLS (55), it should use the normal paddle/switch strategy (2 normally open switches, NO resistor ... )

So, you are saying that both the up and and down shift buttons make it upshift? If this is the case. perhaps the down shift button is mis-wired at the N135. I can't imagine WHY this might have happened, but it is the simplest explanation.

IF you provide a picture of the part number label on EACH shift button AND a picture of the shift button connectors (plugged into the N135). it would be helpful.

Chris

Hi Chris

Thanks for the fast response.

Yes it is CLS55, model 2005. But I think it do not have its original steerning wheel.

what is N135 and how I can reach it? I attached the label on both switches

The N135 module should be under the airbag (to the right).

Ok, I will so it at next time when I will remove the battery. I do not want to remove airbag without removing the battery.

I am curious how it should be? You are saying the shouldn’t be other switch open and other closed (other connected to 12V and other end to the GND)? Or should both be routed to the separate ports of the N135?
You can see a red wire at the up shift button side. Other wire from the up side is similar looking green wire than down button has (only two wires there on both side. The low paddle has same looking green wire than up side has, the other wire of the low paddle is black colored.

you don't need to disconnect the airbag, you only need to back off the screws and move it slightly to the left to view the N135 (and the shift button connections), so disconnecting the battery should not be required. YES, in the CLS configuration, there should be 2 separate connectors (plugged into the N135) .

Hmm, I have to get one oh those tiny thorx tools to access there. I will get in touch later.

I jus wondered would it explain if there is only one connected? Shift to high works and the shift to low also shift to higher. There has to be two connected, am I wrong? Could it be just coded to work like that?