List of MB B EV owners who experienced sudden lost of drive

Below is a list of owners who experienced sudden loss-of-drive issues (either sudden shift-to-neutral, or sudden stall, or sudden loss-of-power, or sudden loss-of-drive)

These are the ones I found, so this list may not be complete. Further, it's my guess only 20% to 25% of MB B EV owners are members on this forum. If you know of others please post below or PM me, and I will update the list. If your car is listed below please keep me posted and I will update your status. The 2014 Bs started selling in the U.S. July 2014, so this list is likely not complete.

I have confirmed with MBUSA that they are monitoring this thread (how often I am not sure). MBUSA is of course welcome to respond here, but so far they have not done so.


Date-of-first-report / Who / Model Year & Production Date / Symptom / Status or Notes
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10/23/2014 / TonyWilliams / 2014 / sudden loss-of-power / occurred one time only, resolved with firmware update, never occurred again

6/24/2015 / Starshoes / 2014 / sudden shift-to-neutral / status-unknown ( http://www.mybclasselectricdrive.com/forum/viewtopic.php?f=8&t=359&p=2746#p2746 )

6/24/2015 / phototrek / 2015 / sudden loss-of-drive after firmware update / happened only one time, owner will let us know if it happens again

6/30/2015 / aloizi98 / 2014 / sudden shift-to-neutral / in-shop, waiting to install new drivetrain

7/5/2015 / TomD / 2015 / sudden shift-to-neutral/ might have been user error, received firmware update, car has been ok since ( http://www.mybclasselectricdrive.com/forum/viewtopic.php?f=8&t=359&p=2836#p2836 )

7/10/2015 / Simonb / 2015 / sudden shift-to-neutral / Front-SAM module replaced 7/17, car has been good since the fix

7/12/2015 / tom / 2015 03/15 / sudden loss-of-drive / local MB tech unable to determine cause of stall, contacted MBUSA, updated firmware of PTCU and AAC

7/19/2015 / Senqua / 2015 / sudden shift-to-neutral / in MB shop for diagnostic ( http://www.mybclasselectricdrive.com/forum/viewtopic.php?f=8&t=359&p=2968#p2968 )

7/24/2015 / vakilak / 201x / sudden shift-to-neutral / will contact MB soon ( http://www.mybclasselectricdrive.com/forum/viewtopic.php?f=8&t=359&p=2992#p2992 )

8/3/2015 / pharmama / 2015 01/15 / sudden loss of power / got car back after 30 days at MB shop, car has been ok since ( http://www.mybclasselectricdrive.com/forum/viewtopic.php?f=8&t=359&p=3048#p3048 ). Update 3/20/2016: MBUSA bought back the car because of sudden loss of power issues.

8/22/2015 / NotYourMom / 2014 / sudden loss-of-drive / new firmware on Aug 27, car has been ok since ( http://www.mybclasselectricdrive.com/forum/viewtopic.php?f=8&t=359&p=3228#p3228 )

8/24/2015 / SuperB / 2015 / sudden loss-of-drive / will bring to MB shop soon ( http://www.mybclasselectricdrive.com/forum/viewtopic.php?f=8&t=359&p=3236#p3236 )

8/28/2015 / Jeff / 2015 / sudden loss-of-drive / local MB service tech installed new firmware, car seems ok again for now ( http://www.mybclasselectricdrive.com/forum/viewtopic.php?f=8&t=359&p=3276#p3276 )

9/19/2015 / CM23 / 2015 / sudden loss-of-drive / power train control unit gateway replaced, firmware updated ( http://www.mybclasselectricdrive.com/forum/viewtopic.php?f=8&t=359&p=3372#p3372 )

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Read following thread to keep up with these sudden-loss-of-drive stories:

http://www.mybclasselectricdrive.com/forum/viewtopic.php?f=8&t=359

Also, here is my guess as to how many MB B EVs are on the road as of 7/2015:

MY2014 MB B EV: 750
MY2015 MB B EV: 1500

# of members on this MB B EV forum: 416 as of 7/12/2015

# of members on Toyota RAV4 EV forum: 1,122 (Between 2012 to 2014, total of 2,600 RAV EVs were produced)

Do we really need 6-7 threads for the same issue?

TonyWilliams said:

Do we really need 6-7 threads for the same issue?

Click to expand...

Good point Tony. I agree, we don't want the multiple threads that we currently have.

The problem is we don't have an active moderator on this site, and over time the threads are created by various people (e.g. one thread from you Oct 2014). If we had an active moderator he could simply fold them into one thread when appropriate

I do think this particular thread I started with the list of all MB B EV owners with lost-of-drive issue will be useful over time, say six months or a year down the road. I created it with the intent of keeping it up to date as more drivers show up with this problem in the future. It being the very first post that I can edit. It stays on top so everyone can easily find it in the future.

As to the on going discussion of this general issue, everyone should follow: http://www.mybclasselectricdrive.com/forum/viewtopic.php?f=8&t=359

Another question for you Tony: You have been here since day one, and you own the 2014 B. I find it strange everyone with this issue all showed up here in the past 4 weeks or so. Besides your lost-of-power post from Oct 2014, there were no other MB B owners with lost-of-drive issues until June 2015?

The time the car stopped on me last year was already addressed with firmware. The speed sensor is a different issue.

It's not new. Popping into neutral should all be in one thread.

Summary of the problem of the tolerances on the speed sensor being greater than the software is happy with:

http://www-odi.nhtsa.dot.gov/acms/cs/jaxrs/download/doc/UCM474877/RCORRD-15V143-3968.pdf

Sudden lost-of-drive is a serious issue. That's what above list is for.

So, besides your experience from Oct 2014, no one else experienced sudden lost-of-drive until June 2015?

tom said:

Sudden lost-of-drive is a serious issue. That's what above list is for.

So, besides your experience from Oct 2014, no one else experienced sudden lost-of-drive until June 2015?

Click to expand...

If somebody is truly concerned with getting this fixed, make a government report when your car fails. Write all the Mercedes contacts to ask them to work with Tesla to fix it NOW, before a government recall.

Im not sure why you are concentrating on June 2015. The "fatal flaw" has been with the car since it was produced. The speed sensor obviously can work for some amount of time, hence the apparent delayed reaction compared to the RAV4, which has been on the road for almost three years.

Again, my issue with the car previously was NOT THE SPEED SENSOR ISSUE.

Thanks for the new info again Tony.

The B has been on the road for 13 months, it is strange to me why no one reported sudden lost-of-drive issues until June 2015, and then from 6/24 to 7/12 we had six people reporting sudden lost of drive issues (for different reasons, not just jump to neutral).

Again, the list above is not all caused by the faulty speed sensor in the Tesla drivetrain, which causes the car to jump to neutral without warning.

We appreciate your experience and knowledge with the RAV and the B, I think what you are saying is some speed sensors will go bad after several months on the road? and we can expect more sensor failures just like the RAV in future months for the MB B EV? That's news to me, and it may explain why people started showing up here with this issue starting June 2015. Perhaps we will see more speed sensor failures second half 2015 and 2016. We'll see.

(Last 30 days we had four speed sensor failures, per above list, but all were new cars with very few miles on them. So, it's strange there were none from 7/2014 to 5/2015, then we got four reports of sudden-shift-to-neutral the past three weeks.)

My 2015 B, as far as I can tell, failed not because of the speed sensor. My car simply stalled just like yours did last Oct 2014. My car did not jump into neutral on its own.

Anyways, not trying to argue, but to communicate. I think the list above is useful as a thread of its own. It covers all sudden lost-of-drive issues. I will keep it updated. If you or others don't agree, we can fold it into the main lost-of-drive disucssion thread.

Update on SimonB's vehicle:

I have an update on my B-Class. Come to find out that the manager gave me the wrong information about my repairs. The drive unit was not replaced. The problem with my B-Class was with what is called a, "Front SAM" All Mercedes has these control units. They act as an electronic fuse box. MBUSA determined that there was an intermittent fault inside this control unit. The Front SAM was loosing communication with the rest of the vehicle intermittently. When the power train control unit would no longer see a signal from the Front SAM, it would shift to neutral.

The fix for this was to replace the Front SAM unit, program the new one and reprogram the power train control unit to accept the new Front SAM.

I have only driven the car about 20 miles so far, so I will wait on the final judgement to see if this corrected it.

Simonb said:

Update on SimonB's vehicle:

I have an update on my B-Class. Come to find out that the manager gave me the wrong information about my repairs. The drive unit was not replaced. The problem with my B-Class was with what is called a, "Front SAM" All Mercedes has these control units. They act as an electronic fuse box. MBUSA determined that there was an intermittent fault inside this control unit. The Front SAM was loosing communication with the rest of the vehicle intermittently. When the power train control unit would no longer see a signal from the Front SAM, it would shift to neutral.

The fix for this was to replace the Front SAM unit, program the new one and reprogram the power train control unit to accept the new Front SAM.

I have only driven the car about 20 miles so far, so I will wait on the final judgement to see if this corrected it.

Click to expand...

Thank you for your timely and encouraging update Simonb! Please come back and give us an update in the future.

Added pharmama to LIST in OP ( http://www.mybclasselectricdrive.com/forum/viewtopic.php?f=8&t=359&p=3048#p3048 )

Added NotYourMom to LIST in OP

Here is NotYourMom's description of his incident of loss-of-drive: http://www.mybclasselectricdrive.com/forum/viewtopic.php?f=8&t=359&p=3228#p3228

Added SuperB to the LIST in OP

Here is SuperB's description of his loss-of-drive incident: http://www.mybclasselectricdrive.com/forum/viewtopic.php?f=8&t=359&p=3236#p3236

Added Jeff to the list in OP

Here is Jeff's description of his loss-of-drive incident: http://www.mybclasselectricdrive.com/forum/viewtopic.php?f=8&t=359&p=3276#p3276

I have confirmed with MBUSA that they are monitoring this thread (how often I am not sure). MBUSA is of course welcome to respond here, but so far they have not done so.

Added CM23 to OP

Here is CM23's post of loss-of-drive: http://www.mybclasselectricdrive.com/forum/viewtopic.php?f=8&t=359&p=3372#p3372

Hi Everyone,

I have not been here for a long time because I've been busy.

I was told MBUSA bought back pharmama's car last week because of sudden loss of power issues.

tom said:

Hi Everyone,

I have not been here for a long time because I've been busy.

I was told MBUSA bought back pharmama's car last week because of sudden loss of power issues.

Click to expand...

I thought Mercedes had the issue fully in control now with the updated software. It that not the case or was pharmama's car bought back before the update was released?

saabluster said:

tom said:

Hi Everyone,

I have not been here for a long time because I've been busy.

I was told MBUSA bought back pharmama's car last week because of sudden loss of power issues.

Click to expand...

I thought Mercedes had the issue fully in control now with the updated software. It that not the case or was pharmama's car bought back before the update was released?

Click to expand...

The person who took the car back from pharmama said he has done 5 of them here in the SF bay area.