Have 2007 sl55 33,000 miles on it.
Not sure if this is related but pretty sure former owner spilled something in center console buttons. Passenger mirror button is totally stuck and other buttons like ride height etc feel sticky as well. I sprayed some electrical contact cleaner in there from on top and didn't do anything. I bought a new part off ebay but didn't have it installed yet.

Anyway today was driving and wanted to put car into manual mode . But when hit the button on the center console it didn't go out of S Mode. Its always gone in properly had car for few months . But no way and when tried to use stick to shift it also just stayed in D on dash display didn't go to other gears. The car was actually not shifting properly either it was staying in Drive or something like that. The car had no power and was in 4th or 5th I think.

I went home after about a 15 minute drive like this and then turned off car and restarted and think was playing with a few center console buttons.
Possibly parktronic or distronic?
Anyway the car started working normally can put it into manual mode and can use paddles and stick was working properly in manual and car was once again shifting properly in both full auto mode and manual modes is back to being fast as f@@k.
Anyway have something like this happen to them? I will likely get that center console changed out asap next week maybe some switch is sticking in between or something or sending some weird signals to computer /tranny.
I see no dash lights . Was also wondering if this could be limp home mode does the car not allow manual shifting when in limp home mode? And does it just stay in a higher gear. But heard if it goes into limp home would get some check engine light and pretty sure not seeing any. Will take car for another drive after supper when it cools off outside and see if its working right. Hopefully nothing serious as have no warranty on the car.
This is my second Mercedes have ML350 had for about a year and just got the SL55 few months ago. I love the SL55 but hope its not going to be some big issue right off the hop .

I used to mostly be a domestic guy and have to say my newer corvettes and my fourth generation firebirds were very reliable and pretty easy and cheap to fix if things went wrong. But had low miles and none of those cars ever saw warranty for anything other than very minor stuff.
The SL55 is a supercar but have read some scary stuff on here about their reliability.

 

I have seen in other models (SLK and E class) where a malfunctioning touchshift switch (activated ie shorted while NOT in "D") will disable the touchshift altogether until the next time the car is started. It stands to reason that if your car disabled the touchshift for this reason ... it would similarly be smart enough to disable manual mode (since you CANT drive in manual mode if touchshift is disabled).

I would be concerned about the spill you mentioned. Many liquids that are sticky are also corrosive. Cola being one of the worst offenders. In other models, this often leads to shifter failure. The button pack with your mirrors and ABC control etc is not inexpensive either. These sub-assemblies are likely serviceable buy a good indy now .... later the electronics in the shifter may be beyond servicing.

Chris

 

I got a hold of a another switch assembly off eBay. So will be installing that shortly.
I have had no problems since the one incident and have driven the car maybe four or five times. That assembly was of course huge money thru dealership but got it for like 150 bucks online. But got used one not brand new.

 

Update. Problem has not reappeared . Happy camper but do wonder why it did that .
Also my console buttons that think had something spilled in them seem to be working now too. I did spray a lot of electrical contact cleaner in there and maybe it finally freed things up. So have the spare part but can keep it for spare not bother putting it in unless have to.

 

Well spring time. I put car away end of the season and it was doing things again. It acted like it was in neutral but managed to get it home after awhile without having to tow it.


I just recently checked tcu to see if any oil had gotten in there but found it to be bone dry. So don't think that is cause of my problems.


I also purchased an upgraded transmission plug and a filter to do transmission fluid change. I broke paddle shifter by catching it on my belt bought replacement ones for reasonable price off ebay.


I managed to get pretty much all the buttons that were sticking on center console and radio unstuck with electrical contact cleaner . It took awhile but they all seem to work now. So not sure what else problem can be. But its making me think will get stuck towing the car to the dealer and afraid to take it out of the city with it doing whats its been doing.

 

My SL500 did exactly the same..
95% sure one of the internal speed sensors in your transmission are dead.
manual mode is disabled if an error code is thrown,
Engine light does not always light up

Replace the conductor plate in the tranny, pretty easy job.
Lots of DIY's around.

Regards
Per

 

More update. I did spray the connectors to the tcu with contact cleaner even though didn't see any oil in the tcu .
I took car to dealership. I had broken paddle shifter by catching it in my belt last season.
So replaced those ,got them pretty cheap off ebay lot less than dealer wanted.
I also changed out trans fluid. Car has 33ooo miles and it did say to do it at 40,000 miles and or think 5 years and of course car is older than 5 years now.
The fluid looked ok dark but not gritty with metal ,magnet looked good. Change out filter of course at same time and changed out trans plug as well to newest version.
So far car has been working great no funny stuff . So guess see how it goes. Reading various things can be reason. The sensor under the gas pedal. intercooler pump can do stuff as well if its failing, the switch by the shifter and the stuff in the trans valve body as was just mentioned.
I did see a code once PO730. Think that was only one seen.
Right now not seeing any codes and car is working right now as it should be.
Guess just take this one day at a time for now.