tode

That is not correct - I have a 2011 W221 and there are definitely two batteries. The one in the trunk is quite well hidden, however !

Jason B

That must have something to do with it being a S350 Diesel.

Nuru

Actually, it may have something to do with the amount of accessories, as I have only 1 large battery and it is a large one in the front of the car. I had to take out the rear seats and all the trunk paneling to get the Fridge retrofitted, and there is definitely room for an extra battery, but my car does not have one. My car does not have the rear seat package, which seems like it would require a lot of power when added to the rest of the car's resident electrical clients.

Nuru

Hmm, where in the trunk is your second battery? Are you speaking of the box visible beneath the Rear SAM?

Nuru

[QUOTE=tode;64 I have removed the trunk paneling, the rear seats to retrofit a Fridge into my car, there is no second battery in the car's rear. The place where it it would go just has harnesses, wires, the Rear SAM located beneath the Fuse holder tray. See the attached pic, I would imagine the second battery would be placed in the open space to the right of the Rear SAM (in center with Fuse tray on top of it) in my car.

Anyone have a pic of the second battery in a 2010+ car?

tode

It's on the bottom right, behind the rear panelling of the trunk.

It doesn't appear to be diesel-connected, since petrol (gas) S classes have one as well.

I believe it's fitted when the car has the Eco Stop-Start function, which is standard over here, but may be optional in the US (?).

Jason B

It's gotta be something on European models only. There is no start/stop feature on US 2010-2013's thank goodness. I'd have it disabled as it drives me nuts. I'm 99.9% sure no 10-13 USA based W221's have a 2nd battery. The real question is, why did they remove it. I'd love to know.

Nuru

so would I. I could have used that for some non-OEM accessories - like another fridge!

Nuru

Ok, within the last 2 weeks, the last N0x sensor replaced had to be replaced again. it may have been an error in part numbers as the sensor failed prematurely and had to be replaced. All good now.

Nuru

Anyone with an S350 have this experience?

I was driving the car for the second time today and all of a sudden, I could not accelerate past 60 mph, and the car while in gear would rev to 3500 rpm and then act like the electronic governor was kicking in. Once I stopped the car and restarted, everything was ok. I received no alarms, idiot lights, or error codes?

Any suggestions

Nuru

additional symptoms are:

I put the car in Distronics assist mode and it switched to "Distronic Override" and as I went down a hill it gradually sped up. Once it was at a good speed, I could set Distronic and it held that speed. However, when I got off the freeway it went back into the slow mode where the car would only accelerate slowly up to 40 - 50 mph and then no further - rpms no higher than 1500 to 2000. When not in gear it will rev freely when in that defective mode. When in that mode, I can shut the car off and then turn it back on, and it acts like a reset and works normally. The defective mode has only shown itself to come on when I am accelerating up this one inclined road very soon after startup. This mode has only started happening in the last 2 weeks. It did not manifest itself in the previous time I have had the car.

Nuru

In thinking about this two things stick out in my mind:
Faulty potentiometer on the gas pedal - Faulty gas pedal, fixing to go.
Turbo could have an issue and the system is trying to protect it by shutting certain things down.

alx

If no check engine light - it is a Clogged fuel filter. Remember- there is no throttle body and there is no vacuum in the Diesel engine. Rpms are controlled by the amount of fuel injected into the cylinders.

This is very common. Especially if you are in a habit of using regular diesel fuel and put in biodiesel- which has high detergent characteristics and will scrape sludge from fuel system which and the goo ends up in fuel filter.

Once shut off sludge goes to bottom of fuel filter and then takes some time to clog again once the engine is restarted.

It could be many other things but a clogged fuel filter is most often the culprit. Throttle rheostats go bad, but can easily be troubleshot with star/ das.

On batteries- 07-09 have 3 batteries- under hood, in trunk and a small battery under dash. 10-13 have two batteries (under hood and under dash) unless diesel which still has 3 batteries.

Nuru

Thanks alx. with regards the to the fuel filter, I only have used regular low sulfur car diesel in the car. Seems that once a fuel filter gets clogged, it probably would not exhibit an intermittent problem and would not recover everytime with a restart of the car? Since it recovers immediately with the restart of the car, I am thinking it is something that the system is seeing something and is taking some precautionary measures, but is not required to present a visible alarm to me yet. I did not look at it yet with a DAS/XENTRY W/S, but that will happen on Monday.

Really weird, as once the car turned off and right back on, the issue goes away, today it went away and then resurfaced while I was driving and forced Distronic to drop speed down to 40 mph until I started going into an declining road, then the car could slowly accelerate, and then Distronic was able to temporarily hold the speed, then it drop again when I started going up the hill.
That fits the fuels filter scenario, but initially I noticed this symptom occurred once within 2 minutes after starting the car the first time during the day and would not show it self again after the restart, even with multiple stops where I would leave the car for a few hours and then come back to restart it?

My car has only the large battery and the small one under the dash.
I am hoping it is something pretty simple and once I find out I will report back here to let everyone know.

Nuru

Well, a trip to the dealer and the problem was in the transmission. The transmission's Electro-hydraulic control unit went out.

Nuru

Well, I am going back to the dealer as it started happening again. So something else is going on Maybe the fuel filter

sloanbj

You car seems like a disaster. I hope you live near the repair shop. I would drive the vehicle into the nearest body of water if it were mine. Euthanasia.

Nuru

Uh, not really, I am sure you would - being in NorCal, you, especially if you are a native NorCal person are not a quitter with a few issues covered under warranty. This car's repairs have not been very expensive at all with the lower turbo seal being the most expensive at ~$1700. The transmission module was estimated about $1500 bucks. Both were covered by the warranty, so no worries and this is out 3rd/weekend car, not a daily driver. The N0x sensor repairs run about $600 each, but these can be done pretty easily by running your car 's rear wheels up on ramps and dropping and replacing the sensors. The current issue may just be a combination of the tranz module and the fuel filter.
i have a dealer within 8 miles and i have great independents (with former MB techs who are experienced with the Developer's mode and the prohibited menu) within 7 miles. so I have no worries.

gsholz

Have you ruled out your electronic accelerator pedal?

I had a problem with my electronic accelerator pedal in a 55,000 lb coach going down a mountain pass. When I released the pedal it would not fully go back to zero and thus the Jake brake would not come on. Coming down the mountain with only the fading service brakes was a nail biter. There is very little engine braking in a diesel.

It turns out that shutting the engine off and on again renormalized the accelerator pedal input to the ECU and everything was fine again. I just did not know that coming down the mountain.

Since you get normal behavior after you turn off the engine, you might try lifting the accelerator pedal fully and cleaning the mechanism.

Nuru

Yep that was okay. BTW, the engine revs normally when the car is put into neutral even when this condition is occurring.

Nuru

Latest Update - one of the tubes (downstream charged air hose) that transports charged air from the turbo to the engine is leaking and it has to be replaced. Since it is a wear item is it not covered by the warranty <$700 installed. It is on the back of the engine in a very tight spot.

gsholz

I'm surprised MBZ considers this a wear item.

Is it this hose?
http://www.mbpartsworld.com/p/Merced...215281582.html

$104

Losing charge air would cause performance loss but hard to believe a leaking hose would fix itself when you restart the car.

Nuru

Yep, that is the part. I found it for $54 from a source in Europe that ships to the USA, and I also found it for $83 at getmercedesparts.com. I was surprised too, but it is supposed to be a flexible high heat tolerant hose, not a metal pipe, and some Manufacturer's cover some hoses and a lot of them don't. When the computer detects it has a leak, it won't let the turbo boost. Seems that sometimes when the car is accelerated on an incline the leak gets to the point where the computer can detect it and then it cuts the turbo, and wallah, no boost, no acceleration beyond 50 mph.

T.H.Carrera

what a nightmare the this diesel engine is.

Nuru

Oh, well, it is actually ok, I have has a few issues, but nothing that would have hit my wallet hard enough to make me scream "I am going back to the E-class!", well not yet at least LOL!. One does not purchase one of these cars used without knowing the risk.