As I pulled into my garage tonight the dash display read "Brake Failure - Workshop" just as I parked it. I turned the car back on and it displayed it again just as I put it in gear. The breaks did indeed not work. Is it from snow? Cold weather? Do I really need to get it serviced?

I'll try to let it warm up in the garage for a few hours and try again.

Tags: Brakes, Drive, Electric, display., failure

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I've spilled water in the trunk and haven't had any problems. And when it was raining my shoes were wet and the water got on the floor and nothing happened. My ED has been flawless, 8 months.


Same story here, Smart ED bought in July (2014). Lots of snow mixed with rain the last couple of days. I use the car in the morning, no problem. Take it out for another ride in the afternoon; I pull out of the driveway, lights come up in the dash (Brake malfunction, workshop) and I have no more brakes....! This is as close as I ever been to smash a car due to a computer failure ! Why does the car computer let's you drive off knowing the brakes don't work ? If I forget to unplug the charging cable, the car won't let me put it to "D"rive and a message appears letting me know the cable is still plugged in. This is a major software flaw. I can't believe there is no literature in the manual about this particular "problem" . Called roadside assistance, it's at silver star Mercedes in Montreal since yesterday. No news for now. 

Anyone from Smart/Mercedes reading this : you guys have a recall breathing down your neck. This situation/problem is an accident waiting to happen . The car should NEVER be able to be driven in this particular situation. 

Will report with outcome later next week.

For the record, my car is set to french language and the message was "DÉF FREINS, ATELIER" : translates to BRAKE MALF, WORKSHOP

also, I never spilled any liquids in the trunk, I even have a blancket to protect the trunk, so the problem will be coming from somewhere else.



I'm glad nothing happened to you. I remember how scary it was when my Smart wouldn't brake due to this mis-design. Please let us know whether your Mercedes dealer also identifies accumulated water under the passenger foot mat (corroding the fuses in the fuse box there) as the problem. It would also be nice if you could let us know how much Mercedes charges you for the repair.I was charged around $400 for "repairing" a problem that is designed by Mercedes into the car and can cause incredible damage to property and life. That expensive repair didn't fix the cause for the problem and therefore I'm now very careful about letting people with wet boots, etc.into my Smart.

Good Luck,


Hi Manfred,

I would be outraged to have a 400$ bill after having that car for less than 6 months. I live in Canada, where the warranty is probably different than in the US. We'll see about that.

Regarding the water damage, no one here flooded the car mats/trunk with the intent to damage the car. We all used the car in a "regular" way where snowy boots and rain water will get on the floor from time to time. I for sure, did not do anything special the last few weeks regarding the level of water entering the vehicle from myself or my passengers ( I actually never did for any of my cars and writing that down just sounds stupid)

I have winter car mats that I empty once in a while , that's the only "precaution" I put into the floor protection.

I'm in Montreal, Quebec and cars sold in Canada have to be winterized : most car maker will offer more options , this is a list from the Canadian Mercedes website regarding cars sold in Canada:

  • Heated windshield washer system;
  • All-season tires;
  • Heated exterior mirrors;
  • Factory/VPC applied undercoating for corrosion protection
  • Other equipment and/or modifications specific to colder climates.

I have no clue if that also applies to their Smart division but I'll find out fast enough. 

Let's see what are the options here.

Thanks, this is the only forum where I could find people with the same problem and happy to share to warn others, and learn from everyone's experience.


Hi Frederic,

I had my Smart for 7 months when that happened. Mercedes was relentless in claiming that this would not be a warranty issue. There was never any visible water we could see. It just accumulates down there and due to Mercedes's design of putting the fuse box at the lowest point where any potential water accumulates with no way to drain it is just a terrible accident waiting to happen. But according to Mercedes that is not a warranty case since it must be caused by the driver who must have put the water in there somehow.

In my mind this mis-design deserves a recall to really address the problem and make sure no one is hurt by suddenly loosing their ability to brake with no prior warning whatsoever.

Obviously Mercedes sees this differently and seemingly takes a wait-and-see approach despite knowing about this potentially deadly problem of their design.


My dealer covered it.

Would be interested to hear how this is resolved.  Are the brakes (other than regen) different than the ICE cars? If you look on SCoA you'll find several threads on the ICE cars being immobilized when/if the brake lights switch (located within the brake module) fails.  No brake lights, the car will not let you drive off. There must be a different failure mode for the ED that somehow bypasses that safety feature....? 

PS - smart must have seen a reason to go from a floor mounted brake assembly to a suspended brake assembly on the new 453 cars....

Think about it. There is probably an electric pump for the brakes.

There is a brake force vacuum pump listed under fuses in the owners manual.  However, as on the ICE cars, even if the power brake booster fails there should be hydraulic braking available. 

Jonathan Gourd said:

Think about it. There is probably an electric pump for the brakes.

There is when this failure occurs. Otherwise I would have hit the back of my garage.

Ok, dealer found some corrosion on vacuum pump connectors. Waiting for parts. 

All under warranty . Strangest thing is they found no water/humidity where the connectors are located. They are going to replace them , I asked if they were "protecting" the new connectors with some housing/grease.... They could not answer right away , they will receive the parts next week.

I still will have a good talk with the dealer when the car is repaired and ready to go back on the road. 

Thanks to everyone who chimed in . Will let you know the extent of the repairs when all is done.


Great to hear that you - like Jonathan - got this repaired under warranty! Too bad they made me pay almost $400 for repairing/exchanging the corroded parts.

The main question though is the one of safety. How come these parts corrode? Moisture seems to have been the reason with Johnathan's and my Smart. What caused it in your Smart? How come the result of that corrosion is such a dramatic sudden failure of the brakes? What can Mercedes do to protect their customers from this safety issue?

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