szulkarn

Recently got an 05 e55. felt the shifting was abit weird.

in any mode, S, C or M mode when i push the steer switch button negative, sometimes it
a) won't downshift,
b) downshift, but automatically will go up to D mode
c) downshift for a while, and then automaticcaly goes up to D mode.

when i tried to use the gear stick to nudge to the left (negative) all of the above happens too.

so I thought, maybe the conductor plate, or the transmision plug is bad...
the odometer is at about 53k Km. so i thought i go by doing a drain and fill, while at it. i bought and replaced the conductor plate and the plug.

after so, i went to do transmission reset adaption, using Das.

started the car, stick to D. S mode, when i press the negative steer switch, it went to 1, and then 2,3,4, back to D. same goes with manually using the gear stick.
tried again, all of the above happened again as previously before the oil change.
i guess the conductor plate and the plug wasnt the issue.

i plugged in the Das, and went to Transmission, and search for switch, there i see steering switch left says not operated, while the right steering switch goes operated, then not operated and loop itself as if theres a continuous on and off contact.
Video in this link "

DAS transmission test

"

i went further step, and remove the switch, positive (right) side. inspect the cable all looks good. i decided to unplug the 12v battery and unsolder the switch from the 2 red and brown cables.
i multitested the connecting point. and check for continuity conclude that the switch itself wasnt the issue. i assume the switch is a N.O switch ( its supose to open as natural state, when i press the button the switch is closed and therefore continuity.)
Video in this Link

"Multitesting the switch"

i took a step further and remove the airbag and check the cable the switch connects to the volume up and down buttons. all good.

out of curiosity, i unplugged all the cables thats in the airbag (except for the horn, and multicolored cables that is plugged in the airbag itself.
turn on the car, S mode, gear at D, nudge the gear to negative. same problem still.
sometimes it downshift to 1 and then 2,3,4 back to D
sometimes it doesnt downshift at all.
sometimes it downshift to 1, i can nudge to gear to the right (+) and it will go to 2 and stay, 3 and stay but alas, it will still automatically go uphift back to D.

this tells me that the steering switch is not the problem, seems like the problem lies in the gear stick itself.
i thought, what if i nudge the gear to the left to downshift and hold it..true enough. nudging and holding it keeps the gear at 1. doesnt go up anymore.
but when i remove my hand and the gear goes back to the middle.. 2,3,4 and D again!.
i havents opened the gear selector module yet..is there a switch ? what could it be?

i am at a loss here. not sure what could be the problem.

took the car for a drive and tried manual mode... the car just upshift itself at automatically...
driving in S or C mode is the same. while driving, sometimes downshifts and then automatically upshifts itself back to D.

does anyone know what could this be? kinda sad not be able to experience the full range of RPM when doing hard pulls in this beast.

fazxs

The issue you have mentioned in your post is exactly what I have and have been living with. During my last visit to the dealership, I wanted this fixed and they tried and probably messed it more. The tech is unsure of what needs to be done.

There is an interesting thread recently being discussed here and I believe the tuned TCU will fix the issue.

https://mbworld.org/forums/w211-amg/...ml#post8237100

I will ordering one this week. Hopefully it enables the proper drive modes that our cars should’ve had from get to.

GinDistiller

I've heard of others with failed gear selector modules. I would have taken the same route as you looking into the + switch and since you've eliminated that, the gear selector sticking in upshift would make sense.

I don't think they are hard to replace, so I'd search for gear selector issues and see what other diagnostic criteria can be found before blaming it. Or, maybe you can find a cheap used one and try it out.

O-55

Check to see if the thread below describes what you're experiencing.

https://mbworld.org/forums/w211-amg/...ml#post3847486

tohu

I had a similar problem and changed the engine oil level sensor and everything is right now! Keep gears changing down! It's just that the sensor itself sometimes gives an error for low oil level and in order not to break the motor computer gives a signal to the gears and raises gears

PieRat

I had faulty engine oil level sensor would cause my car to switch out of manul mode to sport or comfort I can't recall which of the automatic modes. Dealer couldn't figure it out thought it needed a new tcu but I fixed myself with new sensor.

fazxs

Thanks for the information folks. I will try replacing the oil level sensor. Hope it will solve the issue and make the transmission modes work as intended.

Andres Morejon

I'm having an IDENTICAL issue and have been for 2 years. Any update or fix to this? I'd really love to hear it. Thanks