Thump! Complete Loss of Power on Freeway. Went into Neutral

It happened to me at 3500 miles. I was driving my boss around, how embarrassing and dangerous.

Please file a complaint with NHTSA, don't just sit and complaint on the forum

What model year and options does your car have? Any other details about your driving settings at the time of the occurrence?

3300 miles. Driving on 101 at 15mph in regular mode. Thing just shut down and I had to stop the car completely and restart.

https://www-odi.nhtsa.dot.gov/VehicleComplaint/

Wife was driving our 2015 B Class EV (premium package) on the freeway, total loss of drive / power. Plenty of battery power. AC/Radio power was still on. Don't know if it stayed in Drive or switched to Neutral. My wife said all the lights came on the dash. We've had the car for 2 months and it has 1200 miles on it. Complete power down and power up finally - started moving again.

The car has been at the shop for over 2 weeks now, they're waiting on a part from Germany: PTCU-GW (powertrain control unit gateway). Local tech had to send the info to MBUSA as they didn't know what to do. Seems very odd that there are a bunch of these reports in the last 4 months. Also odd they seem to have multiple solutions to the same symptoms. The service manager said they've had one other car with the exact same issue. Guess I'll be driving in the slow lane if I ever get it back. At this rate it won't be much longer before I hit the 30 day lemon law.

In San Diego, CA. Reported on safercar.gov - looks like they have 14 or so complaints between the 2014/2015 B classes. Hopefully everyone posting on the forum is also making a complaint there as well. This is a serious safety issue and from what I'm reading it sounds like they either have multiple problems between the software & hardware or just have no clue what the real problem is.

We bought our Mercedes electric drive on 06/06/2015. The car drives great, but it did stall during driving three times (approximately once per month).
We brought it to the Mercedes dealer, who contacted Mercedes and installed a software upgrade. This was a couple of weeks ago, and today, the car stalled again while driving.
We have a friend who bought the same car in the same month, and her's also stalled already 2 cars. One time on a highway on the left lane, with trucks wizzing by her.
After re-starting, the car is running just fine. However, Mercedes has a huge liability issue, since it is not a matter if someone will get hurt, but when!!
The dealership told us that they have not heard about this problem from any other of the many customers that drive this car. This must be incorrect, knowing that our friend has this problem.
Please report this problem to Mercedes, if you have it!

Report to NHTSA, even better and possibly quicker fix.

My dealer ordered a new gateway from Germany instead of patching the software, which I thought was weird. Hopefully that fixes the problem.

Here is one of the biggest problem when it stalls. Instead of coasting in neutral, the regen mode kicks in and drags the car to a stop even faster. It prevents you from moving to the side in a quick manner as you simply have no time to react!!!!

So I've been getting software warnings only about one a week-- Visit Workshop, engine trouble (RED) not sure I remember what it said, so I stop immediately. But the car drives beautifully. I've never had a loss of power. I pull over, turn the car off, lock it, turn the car on, and go on my way.. 12k miles. Should I be worried?

wtzouris said:

So I've been getting software warnings only about one a week-- Visit Workshop, engine trouble (RED) not sure I remember what it said, so I stop immediately. But the car drives beautifully. I've never had a loss of power. I pull over, turn the car off, lock it, turn the car on, and go on my way.. 12k miles. Should I be worried?

Click to expand...

This does not sound like a complete loss of power failure to me.
Ours had a problem to which yours sounds similar in symptom.
The case was elevated to MB by our dealer and ended in a new front SAM which seems to have resolved the issue completely.
Not the same loss of power problem.

Ah ok please tell me what is a new front SAM -- I only know of the Power train control unit gateway (PTCU)?

From MBUSA: Recall campaign 201500005 with stop-sale order
"Effective immediately, a stop sale is required for Model Years 2014-2015 BED vehicles with the attached VINs. The affected new vehicles that are in dealer inventory must be held, and not retailed, until further instructions are provided. DAG has decided that on approximately 2,618 BED vehicles, the powertrain gateway control unit might send an incorrect signal for a very short duration regarding the status of the high voltage contactor. Should this occur, the vehicle would react to this signal by immediately powering down the powertrain unit. As a consequence, the propulsion power would be lost, temporarily immobilizing the vehicle.

"The recall will be conducted by an authorized MB dealer to update the gateway software on the affected vehicles. MBUSA notified the NHTSA on October 9, 2015 of this new recall, which may generate questions from your customers. There are no parts needed. This recall is scheduled to launch in late November 2015, once the software becomes available. Customer letter notifications will be mailed approximately one week after the recall launch."

Our two MBEDs were in for their battery certification last week, and got the following software update:
Campaign 2015070002: Update Powertrain Control Module, Powertrain Gateway and Air Conditioning Control Module Software.

Hopefully, this is the recall software, and we will not have to go back in.

I hope the a/c update fixes the issue where the cold a/c blows on the windshield, causing it to fog up on hot humid days.

Holy cow, snowds can you provide an official link to something like a press release from MBUSA?

I had posted by in July that I had the same problem with my B-Class, I had no thumping noise, bu the car would just go to full regen and coast to a stop. There was nothing you could do until the car came to a complete stop. Then turn off the car and then restart and the car would drive again. The car was at the dealership for 2 weeks and they had come up with the the front SAM was the problem and installed a new SAM control unit. They stated that the front SAM would intermittently lose connection with the powertrain which would cause it to shut down. Well, 3 month later and 3,000 miles, it has started again. It's back at the dealership, trying again to figure out whats going on.

Nothing is more fun that driving a car in the carpool lane during rush hour and then have your car stall out and no where to go. This is a major safety concern and someone is going to get injured or killed!!

2015 Mercedes B class, 3750 miles.

There is a full recall on all B-Class -- see this webpage:

http://www.nhtsa.gov/Vehicle+Safety/Recalls+&+Defects

ALL B-Class manufactured this far have been affected, and the fix is all SOFTWARE.

Just completed my software update at the Dealership. They told me that Tesla sent them the patch and that my B-Class was one of the first to get the patch.

Sure hope this fixes it.

Just making sure, as with the annual battery certification (desiccant cartridge replacement),
you were not charged any money by the dealer, correct?

Also the recall says the fix is coming in December, do they have the patch ready to install already? Since my B-Class doesn't have the issue, and I got a software upgrade mid -year when I went in for a tire, I'm going to wait until December. My car is a 2014 MY purchased 12/30/2014. 12,000 miles on the odo.

Yes the documents state that it wind be available until November or December, but I can tell you that my dealer was able to get it early. Since this was a huge safety issue for me I got it right away. From what I read in the recall documents it does not appear to be an issue for every B-Class.

wtzouris I can assure you the patch was free of charge and I got a loaner for a couple days while they applied the fix.

While Mercedes words the recall such that they imply that not every car would experience the edge case necessary to cause the problem...The date range of cars listed in the recall appears to be every B-Class manufactured to date, at least in the US.

They probably just want to patch them all to be certain, since technically they are running the code which "could" get in this state.

Our car experienced the power loss for the second time about 2000 miles after the first one which occurred at 1600 miles. My wife was driving and fortunately could pull over and do the restart. I was hoping that the software reflash I did after the first incident would have fixed it but apparently not. I'm really glad MB/Tesla recognized the problem and have a fix now. I don't think I'll wait for the recall notice to bring it in. It's unnerving to worry about when it will happen again. Thanks for the heads up on the recall!