Bad news!
#1
Bad news!
I haven't posted anything for a while here, but I need to at this time. On a trip back home from Akron, OH to Des Moines this past Monday, something very unusual took place with my 2014 S550 transmission. All of a sudden, about 100 miles from home and just after I filled the tank with gas (91 octane), I was not able to accelerate while on the entrance ramp to I-80. It would get stuck on the 4th gear and that was it. The teach would shoot up when I would step on the accelerator, but the speed would not get much higher than about 40-45 mph. This really scared me. Then it occurred to me to manually shift it with the shifter on the steering wheel. Thus, I was able to accelerate to about 65 mph. However, I had to constantly keep pressing the shifter to keep it up on the 6th or 7th gear. Otherwise, it would down shift quickly to 3rd or 4th gear. I did see that the engine light indicator appeared on the driver info screen. The engine temperature was right where it should be at 200 degrees.
About 15 miles (and 15 minutes from home) from home we had the unfortunate experience of getting stuck in a horrible traffic jam (multiple car pileup due to a heavy snow storm) near the I-35/I80 interchange east of Des Moines. We were basically stuck in traffic for an hour and a half. After the mess was cleaned up and we were able to move again, the car seemed to behave normally with the acceleration, but the engine light indicator was still on.
Yesterday morning, I called the dealer and they could not schedule me unto tomorrow morning. So, I have no idea what the problem is with the transmission. It may be a simple as a computer chip going bad. I will report back when I find out tomorrow sometime. I can still drive the car now, but I have not taken it on the Interstate since Monday. Incidentally, the gas mileage for this trip was horrible. I only averaged 23 mpg. I normally get 27-30+ mpg on the highway. I think it had to do with the extremely cold temperatures (5-8 degrees the entire way back from Akron, along with strong cross or head winds for most of the trip. But perhaps the transmission problem may have played a key role as well.
Now for some good news. This car is absolutely amazing on snow with all season tires (RFT's) I might add. I could not believe the amazing control and security I felt passing others at 65-70 mph in the snow. Buying the 4Matic option is a MUST in winter snow climates in my opinion. This was the first real test I had driving the car in snow.
About 15 miles (and 15 minutes from home) from home we had the unfortunate experience of getting stuck in a horrible traffic jam (multiple car pileup due to a heavy snow storm) near the I-35/I80 interchange east of Des Moines. We were basically stuck in traffic for an hour and a half. After the mess was cleaned up and we were able to move again, the car seemed to behave normally with the acceleration, but the engine light indicator was still on.
Yesterday morning, I called the dealer and they could not schedule me unto tomorrow morning. So, I have no idea what the problem is with the transmission. It may be a simple as a computer chip going bad. I will report back when I find out tomorrow sometime. I can still drive the car now, but I have not taken it on the Interstate since Monday. Incidentally, the gas mileage for this trip was horrible. I only averaged 23 mpg. I normally get 27-30+ mpg on the highway. I think it had to do with the extremely cold temperatures (5-8 degrees the entire way back from Akron, along with strong cross or head winds for most of the trip. But perhaps the transmission problem may have played a key role as well.
Now for some good news. This car is absolutely amazing on snow with all season tires (RFT's) I might add. I could not believe the amazing control and security I felt passing others at 65-70 mph in the snow. Buying the 4Matic option is a MUST in winter snow climates in my opinion. This was the first real test I had driving the car in snow.
#4
#5
#6
I am suspecting the fuel because of the engine light indicator and the low mpg you suddenly gut (23 mpg).
Just to eliminate this possibility, I suggest once you empty this tank, you refill with the highest premium fuel available.
I live in Saudi and we have 91 and 95 octane. For Mercedes we use 95.
Good luck.
Just to eliminate this possibility, I suggest once you empty this tank, you refill with the highest premium fuel available.
I live in Saudi and we have 91 and 95 octane. For Mercedes we use 95.
Good luck.
#7
I am suspecting the fuel because of the engine light indicator and the low mpg you suddenly gut (23 mpg).
Just to eliminate this possibility, I suggest once you empty this tank, you refill with the highest premium fuel available.
I live in Saudi and we have 91 and 95 octane. For Mercedes we use 95.
Good luck.
Just to eliminate this possibility, I suggest once you empty this tank, you refill with the highest premium fuel available.
I live in Saudi and we have 91 and 95 octane. For Mercedes we use 95.
Good luck.
Trending Topics
#9
Member
Joined: Apr 2014
Posts: 187
Likes: 3
From: Traverse City, Michigan
2023 AMG SL55,2015 S550 4MATIC, 2023 BMW X5
#10
It's not the gas. Has nothing to do with gas. If gas was the problem you would have hesitation and sputtering. You have a transmission problem. It's either software or hardware. If it runs fine the next day then that leans towards software but doesn't rule out something wrong with the tranny hardware....
#12
MBWorld Fanatic!
Joined: Oct 2010
Posts: 7,548
Likes: 3,833
From: Corona Del Mar, CA
2019 SL450, 2019 E450 Luxury Trim Wagon, 2024 BMW I7 xDrive60
Call me crazy, but after reading a full page article in "Car & Driver" several years ago, I started using regular unleaded 87 octane and have done so for over ten years now, with no problems and excellent performance. My 2013 S550 ran beautifully on 87. That said, I must admit that I am feeling a bit of roughness when my one week old S550 is at idle. So, I am running the tank down to near empty and will fill with premium to see if that cures the problem.
I know we all love our cars and many here like to think of themselves as Michael Schumacher as they pilot their huge saloons through our metro areas, but the C&D article went into great detail about how so much of that extra octane is going right out the exhaust pipe with no benefit, so why pay for it?
I know we all love our cars and many here like to think of themselves as Michael Schumacher as they pilot their huge saloons through our metro areas, but the C&D article went into great detail about how so much of that extra octane is going right out the exhaust pipe with no benefit, so why pay for it?
#14
MBWorld Fanatic!
Joined: Nov 2008
Posts: 1,670
Likes: 13
2006 E55, 2012 Bentley Continental Supersports Convertible, 2014 Kia Sorento SXL AWD
I haven't posted anything for a while here, but I need to at this time. On a trip back home from Akron, OH to Des Moines this past Monday, something very unusual took place with my 2014 S550 transmission. All of a sudden, about 100 miles from home and just after I filled the tank with gas (91 octane), I was not able to accelerate while on the entrance ramp to I-80. It would get stuck on the 4th gear and that was it. The teach would shoot up when I would step on the accelerator, but the speed would not get much higher than about 40-45 mph. This really scared me. Then it occurred to me to manually shift it with the shifter on the steering wheel. Thus, I was able to accelerate to about 65 mph. However, I had to constantly keep pressing the shifter to keep it up on the 6th or 7th gear. Otherwise, it would down shift quickly to 3rd or 4th gear. I did see that the engine light indicator appeared on the driver info screen. The engine temperature was right where it should be at 200 degrees.
About 15 miles (and 15 minutes from home) from home we had the unfortunate experience of getting stuck in a horrible traffic jam (multiple car pileup due to a heavy snow storm) near the I-35/I80 interchange east of Des Moines. We were basically stuck in traffic for an hour and a half. After the mess was cleaned up and we were able to move again, the car seemed to behave normally with the acceleration, but the engine light indicator was still on.
Yesterday morning, I called the dealer and they could not schedule me unto tomorrow morning. So, I have no idea what the problem is with the transmission. It may be a simple as a computer chip going bad. I will report back when I find out tomorrow sometime. I can still drive the car now, but I have not taken it on the Interstate since Monday. Incidentally, the gas mileage for this trip was horrible. I only averaged 23 mpg. I normally get 27-30+ mpg on the highway. I think it had to do with the extremely cold temperatures (5-8 degrees the entire way back from Akron, along with strong cross or head winds for most of the trip. But perhaps the transmission problem may have played a key role as well.
Now for some good news. This car is absolutely amazing on snow with all season tires (RFT's) I might add. I could not believe the amazing control and security I felt passing others at 65-70 mph in the snow. Buying the 4Matic option is a MUST in winter snow climates in my opinion. This was the first real test I had driving the car in snow.
About 15 miles (and 15 minutes from home) from home we had the unfortunate experience of getting stuck in a horrible traffic jam (multiple car pileup due to a heavy snow storm) near the I-35/I80 interchange east of Des Moines. We were basically stuck in traffic for an hour and a half. After the mess was cleaned up and we were able to move again, the car seemed to behave normally with the acceleration, but the engine light indicator was still on.
Yesterday morning, I called the dealer and they could not schedule me unto tomorrow morning. So, I have no idea what the problem is with the transmission. It may be a simple as a computer chip going bad. I will report back when I find out tomorrow sometime. I can still drive the car now, but I have not taken it on the Interstate since Monday. Incidentally, the gas mileage for this trip was horrible. I only averaged 23 mpg. I normally get 27-30+ mpg on the highway. I think it had to do with the extremely cold temperatures (5-8 degrees the entire way back from Akron, along with strong cross or head winds for most of the trip. But perhaps the transmission problem may have played a key role as well.
Now for some good news. This car is absolutely amazing on snow with all season tires (RFT's) I might add. I could not believe the amazing control and security I felt passing others at 65-70 mph in the snow. Buying the 4Matic option is a MUST in winter snow climates in my opinion. This was the first real test I had driving the car in snow.
#15
Don't ask me, but I do. I usually drive at speeds of 75-80 mph. Now as I stated above, there is no way I will get 27-30 mpg when it's extremely cold outside along with a cross wind or headwind as I had on this trip back west from Akron. But the transmission problem may have contributed a little as well for the lousy gas mileage for the trip back.
#16
It's not the gas. Has nothing to do with gas. If gas was the problem you would have hesitation and sputtering. You have a transmission problem. It's either software or hardware. If it runs fine the next day then that leans towards software but doesn't rule out something wrong with the tranny hardware....
#17
Call me crazy, but after reading a full page article in "Car & Driver" several years ago, I started using regular unleaded 87 octane and have done so for over ten years now, with no problems and excellent performance. My 2013 S550 ran beautifully on 87. That said, I must admit that I am feeling a bit of roughness when my one week old S550 is at idle. So, I am running the tank down to near empty and will fill with premium to see if that cures the problem.
I know we all love our cars and many here like to think of themselves as Michael Schumacher as they pilot their huge saloons through our metro areas, but the C&D article went into great detail about how so much of that extra octane is going right out the exhaust pipe with no benefit, so why pay for it?
I know we all love our cars and many here like to think of themselves as Michael Schumacher as they pilot their huge saloons through our metro areas, but the C&D article went into great detail about how so much of that extra octane is going right out the exhaust pipe with no benefit, so why pay for it?
if you drive very very easily and never load the motor up, you might be just fine, but why buy a powerful car only to reduce its power through knock retard?
#19
MBWorld Fanatic!
Joined: Dec 2006
Posts: 6,394
Likes: 300
From: Europe
223.168 & 213.012 & 906.633 & 214.005
For Mercedes we use Diesel (mostly).
#20
Indeed based on Wikipedia, in Europe (Germany for example) you have up to 100, and the mainstream is 95 as it cost more to produce 91 due to low demand.
I think I should switch to diesel too, my car will like it
I think I should switch to diesel too, my car will like it
Last edited by alshaikh85; 01-08-2015 at 03:22 PM.
#21
Ok, the verdict is in. The problem is caused by a faulty boost pressure sensor. It is not allowing the engine to gain full power. Quadcammer, may have had the right idea on his analysis above, but I'm not sure. The dealer had to order the part and it should arrive on Monday. I guess if I understand this correctly, the problem is not very serious, but I'm obviously disappointed that this happened to my car. Meanwhile ,the car is drivable at least around town.
#23
I look forward to getting this resolved early next week, but the car seems to drive pretty smoothly now after being in the shop yesterday. Maybe they did some sort of tweaking. I don't have the "service engine light" any more.
#25
It's actually called "turbo boost pressure sensor". The dealer notified me that it arrived, but I have to wait until Thursday to install it. The service department is very busy.