LSCar

Anyone else have this problem? Our 2011 E550 will at random start out in S mode. Once it starts in S mode, it will not allow you to take it out. The light remains illuminated and the S remains on the speedometer. About half the time, it starts out in E and then allows you to go back and forth as normal. Only 3,500 miles on it and it drives the wife crazy. Today is the third time to the dealer to fix it. We love the car, but the new car smell has started to get a slight lemon scent to it.

Dueclaws

My wife and I would prefer to keep our '12 E550 in S mode and were hoping there was a way to set it and keep it there: unfortunately don't know how to fix yours or ours.

LSCar

Thanks. We could swap them, but I can't guarantee that the S mode will come up as the default every time! The last time I had it to the dealer, they told me it was a suspension strut that was faulty. They replace the strut and the wiring harness, but the problem persists.

sLiQ_e5c

Same thing happen to me about a month ago on my e550, and it wouldnt let me take it off no matter what until about a day later it went back to working normally

LSCar

They have tried to fix it three times. The first time they said it was a short in the wiring and fixed a wiring harness. The second time they were positive it was a short in one of the struts which reportedly is involved in the suspension switch from "E" to "S". Yesterday, they told me their "best man" worked on it and replaced a brake sensor. Only time will tell if they have resolved it. Hope you don't have to go down the same road.

hcetzneb

Not sure if i would jump the gun and say its a lemon because of such a minor issue... with so many electronics on these cars and more coming every year when there is a intermintent
problem it might take some trial and error to resolve

LSCar

Not sure if I agree with you. My particular state gives the dealer three tries to fix a problem, including electrical problems. All cars today have sophisticated electronics. I told them to keep it as long as it takes and they have already had it for an aggregate of over 7 days already. One of our intended primary uses is to travel between homes, about a 120 mile trip each way. To be continually stuck in low gear (even manually using the padels to shift up as far as possible) driving on the open highway is not enjoyable, needlessly imposes wear and tear on the car and substantially impairs the use of the car for our purposes. I agree, it may be minor if we were primarily using it locally, but is a significant frustration when you are using it primarily on the highway. My wife hates the feel in the S mode, so we wouldn't have bought the car if the S mode was the only one available. One option might be to use the M mode (which does take off the S mode), but that defeats the purpose in paying for an automatic transmission. My fingers are crossed that they have fixed it, but only time will tell whether we will continue to be surprised by whatever mode the car decides to be in that day!

ronsc1985

I don't understand your post. If the car is truly stuck in S mode the only difference cruising down the highway is it stays on a slightly lower overdrive gear. The rpm differential is a most a couple of hundred rpm's if that. S mode is hardly distinguishable from E unless you really mash the throttle and then the only real noticeable difference in engine performance is a higher upshift rpm.

Are you really stuck in S or is the transmission failing to get into any of the overdrive gears?

LSCar

The difference is definitely noticable and my recollection is that it doesn't go to the higher overdrive gears (which I could reach if I used the paddles). At first they were focused on the transmission and told me there was an error showing up there. They later told me that they believed it was electrical. If it happens again, I will try to pin down exactly what it allowed me to do.

ronsc1985

I just went on a long trip. Running 75 mph, where in E the transmission is definitely in the highest gear and the torque convertor is locked up, changing to S moved the rpm's maybe 200 max.

I have also been underwhelmed with the difference between E and S generally. Seems to me the only reason to go to S would be for some type of competitive event.

BTW did they check the simple stuff first like the switch itself. As an EE who has troubleshot many electrical systems it has always amazed my how people skip the simple stuff and jump right to the more esoteric.

I lost count of how many times a loose connector, wire etc. was found only after long, tedious and expensive down time. The worst part is after they find the simple fix people usually won't admit it thereby making sure that the next incident will probably go through the same long, tedious and expensive procedure.

LSCar

Thanks. Good point on the possible easy fix. I hope I have this behind me. We really like the car otherwise. I will follow up with the good or bad news.

mattbta

I drive in S and my wife in E. She complains that the car doesn't seem as peppy as the 09 C350 we traded. I've been beating on it in S so it gets used to my habits and it definitely feels like an animal in S now.

I'd love for it to stick in S as sometimes I forget to change it. However, that is certainly a defect if it doesn't start in E and won't let you switch.

LSCar

Thanks. My fingers are crossed, but so far it has operated normally since the most recent service trip.

The 550 on "S" is fun to drive when that is what you want to do, but you really need to be aware of it or you peel out of every intersection. It also gets angry when you accelerate quickly and then take the foot off the gas (it can really jerk your head around if you aren't paying attention). The wife isn't a big fan, so when it isn't in E for her, my left ear hurts.

ronsc1985

What is it they "fixed"?

LSCar

This last time they said it was a front brake sensor.

ronsc1985

The last time the problem came back. If they didn't fix something different I'd have a doubts the problem is cured permanently.

The only reason I mention this is when people post their problems and the real fix it may help others make one and only one trip to the dealer if they have a similar problem.

LSCar

Agreed. Here is the summary, the first time, they said is was a short in the electrical harness. The second time, they said it was a short in one of the struts that was involved in the suspension change when placed in S mode. This time they said it was a front brake sensor.

I am somewhat optimistic this time because the problem resurfaced sooner the first two times we had it in to be fixed. This time, it seems to be working.

ronsc1985

I hope that fixes your problem although what a brake sensor has to do with your S switch is a real mystery.

Brake sensors are usually there to provide a wheel speed input to the ABS system. If the ABS system is compromised I would think you would get an error message upon start up.

According to some friends who have worked as dealer technicians in various brand car dealers they would always replace something even if the real problem was simple such as a loose wire. The factory repair standards/dealer remuneration didn't provide anything like the time it actually took to find and fix the real problem.