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Discussion Starter · #1 ·
My 2013 dead sitting next to my house, is there a non dealer way to reset pyro fuse?
everything turns on and works, radio, lights ac heat etc.
Will not get out of park, code scanner shows pyrofuse tripped.
battery over 90% charge.


Car stopped all of a sudden while driving, had to be slid onto flatbed to be towed home.


FYI there is a key icon on speedo, after it first stopped it seemed like the 12v battery was dead, could not even use code scanner, replaced battery and only code that will not clear is the pyro fuse tripped.
 

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Discussion Starter · #2 ·
so I read this from emergency response guide


Automatic high-voltage disconnect




In the event of an accident, the high-voltage system
can be shut off by the restraint system control unit or
alternatively, by the high-voltage crash sensor control
unit.


If the restaint system control unit triggers an activated
occupant protection system (airbag, seat-belt tensioner
etc.) in an accident, the pyrofuse in the control
cable of the battery contactors is also triggered. The
control cable of the high-voltage system is then physically
disconnected.




In this case the high-voltage output remains irreversibly


deactivated and can only be reactivated by service
personnel.


I think mine had a malfunction, when I scanned car I did see crash sensor errors in the past, car worked 100% so I did not worry.
 

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The pyro-fuse, as its name implies, cannot be reset but must be replaced. The battery pack contactor-relay coil circuit (the low voltage side) is wired through it. These contactors assure the high voltage is safely isolated in the traction pack battery case when the car is turned off (or via the pyro fuse, after a crash)

Fortunately, the pyro-fuse is fairly easy to access - remove the driver's seat and pull the carpet back. The pyrofuse can then be checked with an ohmmeter for an open-circuit.

But what caused the pyro-fuse to blow (like the crash sensors - one would think they are the same ones that trigger the airbags) needs to be diagnosed and fixed too.

Of course, with the overly complex software running everything in the car, I wouldn't put it past MB to put in something that needs to be reset by a dealer even after the pyro-fuse and sensors are replaced.

Edit: Here are a few more things to check - when you switch the car on or off, do you (usually after a second or two delay) hear a deep "thunk" from somewhere underneath the floor? Don't confuse it with the relays on the SAM unit under the dash.

Also, check if the heater and/or AC works - not just the blower, but warm air or cold air and the sound of the compressor running (weather too cold for the latter check right now if you live in much of the US and all of Canada). The heater core and A/C compressor run on traction pack voltage, so if they are working, the pyrofuse cannot be blown. And does the car charge? That is another check.
 

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Discussion Starter · #4 ·
thanks for the advice, will double check for real heat and ac There could have been something under my seat that hit the crash sensor. I had new rotors in back, one fellbehind and under seat, that could have caused issue. I had not even hit a big pothole at all, in past have hit many in ny area. Can the fuse be brought into dealer? can it be jumped? Does dealer need whole car, will I need to buy whole pyrofuse unit? Seems to say in text from above they can reset it.
 

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Fortunately, the pyro-fuse is fairly easy to access - remove the driver's seat and pull the carpet back. The pyrofuse can then be checked with an ohmmeter for an open-circuit.

But what caused the pyro-fuse to blow (like the crash sensors - one would think they are the same ones that trigger the airbags) needs to be diagnosed and fixed too.
Remember that there are airbags in the seats. BEFORE removing - disconnect the 12V!
 

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thanks for the advice, will double check for real heat and ac There could have been something under my seat that hit the crash sensor. I had new rotors in back, one fell behind and under seat, that could have caused issue. I had not even hit a big pothole at all, in past have hit many in ny area. Can the fuse be brought into dealer? can it be jumped? Does dealer need whole car, will I need to buy whole pyrofuse unit? Seems to say in text from above they can reset it.
The airbag-triggering accelerometers on cars are usually mounted in the front bumper area. A dropped heavy object will not trigger them in any case. Normally, one would expect the airbags to go off if an airbag sensor receives a sufficient acceleration. "Reactivate" can mean replace a part.

And yes, you can buy the pyrofuse or any other part from a dealer, or an internet-based MB parts seller - who may also rebuild the fuses for cheaper.

The sensors may not be the problem, the pyrofuse itself may be defective, and also, Smart 451 EDs seem to have a problem with wiring harness chafing failures - so the problem may be a broken wire, not the pyrofuse. But per my previous post, the continuity of the fuse connection can be checked easily enough. And yes, as MB DNA wrote, always disconnect the positive terminal of the 12V battery before disconnecting any connectors needed to remove the front seat or any airbag-related components (or any other electrical work for that matter).

Correct me if I'm wrong, but I get the impression from your questions that you don't have a lot of automotive repair experience. But I fully understand your trepidation about bringing it to a dealer - a lot of Smart Car repairs seem to be driven by MB's bureaucracy and lawyers, not practical mechanics or engineers - such as stories of people being told the car is a total loss (becasue the battery pack must be replaced) when a crash big enough to trigger the airbags/pyrofuse happens. What bull****! (are we allowed to say that word?)

(Edit: Oh, the forum automatically replaces the offending words with asterisks)
 

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Discussion Starter · #7 ·
checking a few things tomorrow, the 12v battery is getting charge from the HV battery, so HV is not totally offline, when key is turned 12v batt goes to 14v
I called the dealer last week to get pyrofuse price, they did not come up with a part number.
Need to call after I look at it and have part numbers from it


thanks for the help
 

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Discussion Starter · #8 ·
OK so here is what happened.

Had car towed to dealer, my code said circuit 15 or something like that
They needed 3 + hours of diagnostic time to find it and fix it.
long story short, they tried to tell me 100 things wrong with car, including that my new continental rear tires are wrong.
I said no to all but my repairs.

$500 later car is ready to be picked up, will update forum when I find out what they found and did, they claim a wire in a harness was broken or shorted?
I guess $500 each 17,000 miles is not too bad.
 

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Thanks for the update. I was going to mention that wiring harness rubbing and wire breakage seem to be a recurring problem with 2013 to 2015 EDs - a really inexcusable design or workmanship flaw in my opinion.

I had it happen to me - in my case a signal wire to the AC compressor - so at least the car still ran. Fortunately it was (and is) still under warranty.
 

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Thanks for the update. I was going to mention that wiring harness rubbing and wire breakage seem to be a recurring problem with 2013 to 2015 EDs - a really inexcusable design or workmanship flaw in my opinion.

I had it happen to me - in my case a signal wire to the AC compressor - so at least the car still ran. Fortunately it was (and is) still under warranty.
Yinzer, is it just the signal wire to the AC compressor that is the problem, or are there other wires that are problematic as well? I haven't experienced anything yet in my 17 months of ownership and still have a warranty for almost another three years, but I'd be more than happy to throw some split loom tubing on the trouble spots if it can prevent a trip to the dealer. Thanks.
 

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Discussion Starter · #11 ·
Please tell me what area are these wires rubbing?
I want to put some armor on that area before I blow some modules.

FYI, after a laundry list of stuff they want me to do, including put the big tires on back again.
I asked them to reset the service reminder, they said no, service was not done.
But the check list they gave me {generic one} said checked oil trans fluid and a bunch of other things I do not have.

I have tried the reset procedure 20 times with no luck, please help!
 

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The reset procedure seems a bit hit or miss. After I had my one and only service at the dealer, the service writer tried to reset the maintenance indicator with no luck. He had to drive it back to the shop, where I saw them work on it for about ten minutes before they were successful.
 

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1. Turn key to position 1

2. While the cluster is still saying "Smart," double click the button
to bring up the maintenance indicator.

3. Release the button and turn the key off.

4. Quickly press and hold the button and turn the key back to position
1. This is while the cluster still has the maintenance reminder on.

5. Hold the button in until it resets to 10K.

6. Worked for me!!

Len
2014 EV Coupe 16,500 miles
2014 EV Cabriolet 8,500 miles
 

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Discussion Starter · #16 ·
So I hope my code Skinner and codes I had for a while or all cleared now so the rubbing caused some other sensors the didn't make it stop I was seeing crash sensors and things like that now they're all clear
 

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Yinzer, is it just the signal wire to the AC compressor that is the problem, or are there other wires that are problematic as well? I haven't experienced anything yet in my 17 months of ownership and still have a warranty for almost another three years, but I'd be more than happy to throw some split loom tubing on the trouble spots if it can prevent a trip to the dealer. Thanks.
I assume that the problem could occur with any wire in the harness wire bundle which is chafing - the wires probably not having the same location in the bundle from car to car.

One other thing they did when servicing the problem was to replace the charging receptacle and associated wiring, they said those were damaged too.

Unfortunately, I was unable to get any cooperation from the dealer that described the specific location or locations where the wire break occurred. Visually inspecting all of the wire bundles in the harness for friction spots would be a chore but probably worth doing - but not something I've ever had to do in any car I've ever had or worked on.
 

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Please tell me what area are these wires rubbing?
I want to put some armor on that area before I blow some modules.
I was not able to get the dealer to cooperate in telling me where the specific wire break or rubbing was, and too much time has passed at this point.

Did you get specific information on where your wire break occurred? The info. would be really helpful to us all.
 
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