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2017 smart fortwo (453)
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Discussion Starter · #1 ·
Hey everyone! 馃憢

I am the happy new owner of a 2017 fortwo with the DCT. It was a lease return, and only has 6,500 miles on it.

I understand that this car has a quirky transmission, but am unsure: how quirky is normal for these cars? I've noticed these behaviors:
  • at low speeds (stop/go in NYC), the car occasionally is very indecisive re: gear choice
    • for example, sometimes it refuses to upshift, so there is significant engine braking if I release the throttle; causes a "washing machine"-like effect where the car is jerking around at low speeds as I switch between gas/brake pedals
  • in certain scenarios there is 0 throttle response for up to 1s
    • example: coast towards a red light as it turns green, press gas, basically nothing happens for 1s
Under other conditions it seems completely fine, but it can get a bit rough/indecisive in low speeds - which, in NYC, is very often.

I can get used to the engine braking effect in city traffic, it's actually helpful and will reduce brake pad wear. I just want to make sure this is normal. The car is still in warranty, if something is wonky, I want to get it fixed!

Thank you =)


64234
 

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Sounds very similar to the 451 model which it replaced... In the "Auto" mode the car's computer controls the shifts. Low speeds seem to confuse the car, particularly if you let off the gas and then immediately try to accelerate - the computer has to go from "the driver wants to slow down" to "now the driver wants to go faster" in a split second but it takes more time than that. The computer only "knows" what you want based on throttle input and brake input - so the smother you are on those the better the car likes it. Remember, even though the DCT is touted as an "automatic" transmission, it isn't - it's a six speed manual transmission, just missing a clutch pedal. The more experience you have with the car the better you'll be able to adapt to its "drive-by-wire" quirks. :)

Great looking car, BTW!
 

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2017 smart fortwo (453)
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Discussion Starter · #3 ·
Sounds very similar to the 451 model which it replaced... In the "Auto" mode the car's computer controls the shifts. Low speeds seem to confuse the car, particularly if you let off the gas and then immediately try to accelerate - the computer has to go from "the driver wants to slow down" to "now the driver wants to go faster" in a split second but it takes more time than that. The computer only "knows" what you want based on throttle input and brake input - so the smother you are on those the better the car likes it. Remember, even though the DCT is touted as an "automatic" transmission, it isn't - it's a six speed manual transmission, just missing a clutch pedal. The more experience you have with the car the better you'll be able to adapt to its "drive-by-wire" quirks. :)

Great looking car, BTW!
Thank you for the helpful reply! I did a ton of research (it's a car purchase, after all!) before buying the car, am aware of all the quirks like it being a DCT (not a real auto transmission). Many reviewers compared the 453 to the 451 (relative), and said it was vastly improved - but none of the reviewers actually commented on the 453's absolute performance. "It's better than the 451, that's for sure!" isn't as much as I'd want :)

Your reply is super helpful, glad to know this is a normal quirk, and not a sign of this car's imminent demise. I've previously driven transit buses, it's very strange going from those to.... this.

and thank you, I'm very happy with the car's appearance. It's borderline miraculous finding an accident-free lease return in NYC, instead of a used car2go or something. I would not want to buy a used rental car, people drive them with no regard for the car's longevity.
 

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If you switch to manual mode, the jerkiness should disappear. I would also take the car in to a Mercedes dealer that services smart cars and make sure that your car is current on any software updates. Play with manual mode and sport mode a bit. You may like that better.
 

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You should be able to just call or send an e-mail to a cooperating dealer with your VIN and find out if your car is due for any updates. I've got a dealer that is very helpful with stuff like that.

Len
 

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Thank you for the helpful reply! I did a ton of research (it's a car purchase, after all!) before buying the car, am aware of all the quirks like it being a DCT (not a real auto transmission). Many reviewers compared the 453 to the 451 (relative), and said it was vastly improved - but none of the reviewers actually commented on the 453's absolute performance. "It's better than the 451, that's for sure!" isn't as much as I'd want :)

Your reply is super helpful, glad to know this is a normal quirk, and not a sign of this car's imminent demise. I've previously driven transit buses, it's very strange going from those to.... this.

and thank you, I'm very happy with the car's appearance. It's borderline miraculous finding an accident-free lease return in NYC, instead of a used car2go or something. I would not want to buy a used rental car, people drive them with no regard for the car's longevity.
The DCT version in the 453 is dramatically improved but still not butter smooth as found in traditional slush boxes. In hot weather with the AC engaged there will be a bit more 鈥渏erkiness鈥 experienced and downshifts from 3-2 and especially 2-1 will be harsher. Characteristic of the breed. Yes, sometimes there is a slight delay in shift response. Most transmissions today, regardless of type, are programmed for economy which means staying in an upper gear a bit longer than some of us prefer.
 

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Same problem here i changed the air filter for washable and it helped with jerkiness at low speed but still noticeable while using AC
 

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Nice looking smart car you own.... It really too hard to diagnose a transmission issue, over any forum. Since your vehicle is still under the factory warrant. Run it by the MB dealership. We had a Dual clutch transmissio, on another car. They seem to shift a little different. Not like any new modern automatic. When they get over heated, in stop and go traffic. The transmissions, need a cooling off period. The dual clutch transmission in the 453 is it superior unit compared to the 451 transmission.
64245
 

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It's normal behavior. The car lurches forward like you accidentally downshifted from 3rd to 1st. Also, it's worse when the A/C is on. It's a real PITA in stop and go traffic. It's best to "float" the throttle at slow speeds. Ease off the throttle at low speeds and allow the car to coast a little before braking. When accelerating at low speeds, again "float" or ease into the throttle slowly. It requires allowing for more following distances when in stop and go traffic. Over time, you'll get the hang of it.

Off topic, I added a GoPedal from Smart Madness. It gets rid of some of that "delay" when pressing the the accelerator pedal and really helps with low RPM sluggishness. It doesn't cure all of the "quirkiness" and I still occasionally get a "lurch". Also, it makes the car so much more responsive and a hoot to drive. Took me about 20 minutes to install, including routing the wire for the control under the center console.
 

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I'm either weirdly lucky or super suited to my 453. Never had any type of jerking or issues when running the a/c. I did get the GoPedal from Smart Madness but have yet to install it. Mostly got it to control the pedal when it's not in my possession
 

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I've made a lot of "performance" mods to many cars over the years: K&N filter/chargers, Platinum plugs, exhausts, etc. The biggest boost, other than adding a turbo, was the GoPedal. Also, it was the easiest to install. Throttle is more responsive and requires less travel before the car goes.
 
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