[twyrick]

I have a 2013 Smart4Two Passion Cabrio I purchased a couple years ago, used. At the time, it badly needed new spark plugs so I changed them out myself, and that got it running much better. Later on, I got a fault code that had to do with part of the EGR system and thanks to these forums, I was able to locate the part to replace for about $35 online and do that myself too. I've had to replace a burnt out headlight and marker light too, but really nothing else except a couple of oil changes.

But one random issue I've had pop up ever since I bought it was the transmission deciding not to shift properly, followed by "D" blinking on the dash. When I pull over and shut off the engine, I just get the 3 horizontal bars on the dash when I restart it. The transmission re-learn procedure of holding down the brake for 30 seconds after turning the key to "on" clears it back up -- but it happens again every so often.

The other day, it finally got a CEL after it happened, and my code reader said P0949 "Auto shift adaptive learning not complete", and P2802 "Transmission Range Sensor B Circuit Low Input". Someone suggested this was probably a clutch actuator sticking and it might need to be taken apart and cleaned/lubricated and put back on? I found the replacement part for sale on eBay but after shipping, it came close to $500. I really didn't want to dump that much money into this car on just one repair part, since I only paid $5000 for it in the first place. So I decided it was time to take it back to the Mercedes dealership that originally sold it when it was new.

They called me this afternoon to tell me they couldn't find any mechanical problems but thought a software upgrade was needed. Charged me $145 for that and said "if it doesn't work, to bring it back in". They also said something about a transmission linkage that was "smashed flat" on the rubber ends? They wanted $175 to swap it out, saying this happens occasionally on the Smarts after they get past 60-70K miles, and the rubber bushings being flattened like mine are will cause excessive vibrations? I've never seen this mentioned anywhere before..... Told them to go ahead and fix it while it's there. But am I getting ripped off?

 

[jwight]

If you can get a part number from them that would help. 🙂

 

[dhlairbusb4]

I hope they are being straight with you. I would have suggested you doing the shift actuator yourself. Its not that hard to remove, take off the cover, clean it out, and relube with white lithium grease, reinstall, and adjust if needed. Also, the transmission relearn procedure is more than holding the brake pedal.... you turn the key on, do not start motor, then hold brake and shift gear selector thru all the gears slowly, including the slide to the left for manual shifting...
Probably too late, but hope it helps if the dealer doesn't.

 

[twyrick]

I hope they are being straight with you. I would have suggested you doing the shift actuator yourself. Its not that hard to remove, take off the cover, clean it out, and relube with white lithium grease, reinstall, and adjust if needed. Also, the transmission relearn procedure is more than holding the brake pedal.... you turn the key on, do not start motor, then hold brake and shift gear selector thru all the gears slowly, including the slide to the left for manual shifting...
Probably too late, but hope it helps if the dealer doesn't.

Yeah .... I would have done the shift actuator cleaning myself, except being on the underside of the car, it made it more of a problem for me. I don't own a set of ramps, for starters. And when I asked a few local independent shops about it, they pretty much refused to do it. (Got the idea they weren't too familiar with Smarts and the weird automatic manual transmission setup, and they just wanted to replace the entire actuator with a new one if anything.) I figured if my car DID need newer transmission software, nobody was going to be able to do that except the dealership too. So just resigned myself to let them take a look.

As for the relearn procedure? I'm aware they tell you to shift slowly through all the gears, but I've tried the process both doing it that way and skipping it -- and I'm not sure it honestly made any difference? Either way, I hear it doing the "click, click, click" sounds under the car as it's recalibrating things while I hold down the brake pedal. And a few seconds after that, the horizontal lines disappear and the "P" comes back. (If anything, I suspect the step where you shift through the gears just helps it re-learn exactly where the lever sits when it's supposed to be in reverse, neutral, drive or park. And in my case, that's not where my problem lies anyway. So when I do that part of the process, it's just storing values that match what it already had stored, essentially.)

I guess at this point, the only part I'm puzzled about this this "wishbone shaped" piece they're claiming was crushed on both rubber ends and needed replacement. I pored over the Smart 451 service manual (which I was able to download a copy of) and I can't see anyplace in there referencing such a part? My car is supposed to be ready for pickup today, if it's not already done. So I guess I'll see the part number on the work order when I get there.....

If the 3 horizontal lines come back after this? I don't think I'll waste any more time with the dealership. I'll find a way to get the actuator removed and cleaned, and maybe try this other advice I saw on YouTube to remove a rubber cap from the top of the clutch motor and spray some lithium grease down in it too. Presumably, the software update they did might at least give the car improved shift points at various RPMs, so maybe worthwhile even if it didn't address my problem?

 

[dhlairbusb4]

If you do that lithium into the gear box, your adding lubricant to the gears that the shift motors operate. Its a vent port, so if its over filled, it will just blow it out.

 

[gtdump]

If you do that lithium into the gear box, your adding lubricant to the gears that the shift motors operate. Its a vent port, so if its over filled, it will just blow it out.

Do realize that by putting lithium into the gears for the shift motors, you are also injecting it the thransmission and onto the shift forks and drum mechanism which is directly below it.

I had also gotten the "Shift adaptive learning not complete" error a little while ago with my Smart. It appears my problem turned out to be the shift motors themselves, the brushes and bearings were shot, which was causing the motors to work only nominally, if at all. 2013 sounds a bit new for that to be an issue, but it's something to consider. (mine is a 2008 with just under 100k miles)

 

[twyrick]

Oops... I meant to follow up on this post, just in case it helps anyone else (or anyone else wants to comment on it!).

When I got my car back from the dealership, it was shifting and driving MUCH better than before. Now that it's been a couple of months? I haven't had the problem again with the transmission going to the 3 bars on the dash. Oddly though? It seems like after several weeks of driving, it's gotten so it doesn't want to shift up or down a gear like it was when I first got it back? For example, there's a fairly steep hill I go down when I leave my house and the car will coast all the way to the bottom of the hill with it in first gear making a loud revving noise the whole way unless I tap on the gas a bit during the descent, which gets it to upshift to second. I don't recall it behaving like this before. From what I can tell, the dealer never actually messed with anything mechanical with the shift actuator. Rather, their programming tool did a full recalibration procedure along with whatever firmware update they said was available. Seems like that might be sort of a band-aid for wear that could have been compensated for by unbolting the actuator and repositioning it a bit before tightening the bolts back up? But these guys sold Smarts since 2008 and my car was supposedly worked on by one of their mechanics that's trained to work with them. So I'm hesitant to second-guess their methods here. I did mention the shift actuator to the service tech specifically, but he told me it passed their diagnostic tests and they didn't feel it needed anything done to it physically.

 

[dhlairbusb4]

You can do the shift actuator cleaning your self, its not hard. Then follow up with a tranny relearn... should be much better after that. If not, then do the gear shift motor cleaning.....