[DreamCarOwner]

I just ran acrossed key and FOB replacements on e-bay and also on wish.geek websites. I jumped at the chance on Geeks to order 2 keys that were complete with electronics and the standard 4 button head like my 2011 451 takes. The frequency was listed as 315 mhz. They were listed as 2005 to 2015. So I ordered them. Then later on ebay I ran acrossed a similar key with electronics and it only showed 3 buttons. It didn't have the red panic button but otherwise looks identical. It was listed as 434 mhz 2007-2013. So am I at a loss as to whether I ordered the wrong keys or not or whether there is some erroneous info in their advertising. Does anyone know what the true frequency of the 451 FOB's are or was there more than one frequency used over the 451's life? 2005 to 2015 doesn't make sense because the 451 years was from 2007 to 2015 right? DCO

 

[jimvw57]

The 451 ran from 2007 to 2015, but the remotes were always kind of a mystery. They need to be programmed with then starr computer to have them work with a specific car as far as I know. Not like some of the U.S. cars that can be programmed by turning the key so many times and presssing the remote.

 

[Huronlad]

The 450 and 451 fobs are very different physically. Search for images on the net.

 

[smark]

I'm not to sure about this. On my other car the key Fob, can only be programed once to that specific car. I don't know if a smart car is like that.

I know from experience. I had to buy 2 new smart key Fobs from smart. Special order, for my car. We lost one key. Couldn't find the backup. The dealer had to program them. the keys cost me over 300 bucks, another 100 to program them. Whats sad. Finally after 7 years. Found the backup key, in a coffee mug, way in back of the kitchen cabinet. Brand new, never used.

 

[Huronlad]

The blade must be cut to match the car. In a 450 any fob can be linked to the SAM, fairly certain the 451 is the same.

 

[Smart Bob]

I believe that the fobs sold for smart car in other markets are only 3 button. The US fobs are all 4 button.

 

[DreamCarOwner]

Here is the one that I purchased from wish.geek and it is 4 button and listed as 315 mhz. I jumped on it at a price of $18.
https://geek.wish.com/search/smart fortwo#cid=5864dd495a477258854c24fb

Here is a 450 key which is very different all the way around.
https://geek.wish.com/search/smart fortwo#cid=56458b39b9fe1a162716d93f

Found this one on ebay that I could have bought. It's listed as 315 mhz.
New Replacement Remote key Fob 315MHz 4 Button for Mercedes-Benz Smart Fortwo | eBay

Then here's one that is 4 button but listed as 433 mhz.
Keyless Entry Remote key Fob 433MHz 3+1 Button for Mercedes-Benz Smart Fortwo | eBay

Then I found this one. 3 button and 434mhz.
3 BTN Uncut Keyless Remote Control Key Fob for Smart Fortwo 451 2007-2013 434MHz | eBay

So it's kind of confused me. I ordered the first one, 4button and 315 mhz. The metal blank is called a laser cut key or a sidewinder key. I can get the blade here cut locally from my original. Then hopefully I can get the Fob's to the Smart dealer in Columbus and get them programed. I was just confused on the proper frequency. And I hope on the long run it works and saved me some money. It would be a shame for me to spend $36 on 2 keys and around $15 each to get them laser cut. That's $66. Then add $100 or so for programing. $166 sure beats $300 for 2 factory keys. I just hope these Chinese knock offs work reliably and last. I guess time will tell. I guess I will have to call the service dept. and get them peroof of ownership to get permission from the mothership? I guess I should have bought a third and just used the FOB part.

 

[toaster]

315 MHz in the USA

Here is the one that I purchased from wish.geek and it is 4 button and listed as 315 mhz. I jumped on it at a price of $18.
https://geek.wish.com/search/smart fortwo#cid=5864dd495a477258854c24fb

Here is a 450 key which is very different all the way around.
https://geek.wish.com/search/smart fortwo#cid=56458b39b9fe1a162716d93f

Found this one on ebay that I could have bought. It's listed as 315 mhz.
New Replacement Remote key Fob 315MHz 4 Button for Mercedes-Benz Smart Fortwo | eBay

Then here's one that is 4 button but listed as 433 mhz.
Keyless Entry Remote key Fob 433MHz 3+1 Button for Mercedes-Benz Smart Fortwo | eBay

Then I found this one. 3 button and 434mhz.
3 BTN Uncut Keyless Remote Control Key Fob for Smart Fortwo 451 2007-2013 434MHz | eBay

So it's kind of confused me. I ordered the first one, 4button and 315 mhz. The metal blank is called a laser cut key or a sidewinder key. I can get the blade here cut locally from my original. Then hopefully I can get the Fob's to the Smart dealer in Columbus and get them programed. I was just confused on the proper frequency. And I hope on the long run it works and saved me some money. It would be a shame for me to spend $36 on 2 keys and around $15 each to get them laser cut. That's $66. Then add $100 or so for programing. $166 sure beats $300 for 2 factory keys. I just hope these Chinese knock offs work reliably and last. I guess time will tell. I guess I will have to call the service dept. and get them peroof of ownership to get permission from the mothership? I guess I should have bought a third and just used the FOB part.

Nice find!

If you open your key and look inside the rear half of the shell, you should find the following ID number: "KR55WK45144".

If you enter this number into the search box at this web site:
https://fccid.io/

It will take you to a list of several FCC documents. The one you want is the "User Manual".
https://fccid.io/document.php?id=778796

This identifies it as 315MHz for the USA, Japan & Australia, while Europe is 433MHz.

---

Now about this geek.wish.com website... Have you ever ordered from them previously? The very nature of their site and the way they want one to register, or provide their social media info, before even allowing you to browse items... well it raises all kinds of flags with me that they are (pick one or more) scammer, spammer, fraudsters, dishonest, crooks, etc


The dimensions of their key seem to check out, with just one small deviation. Where the metal blade connects to the case it is wider than the rest of the key blade. I don't know if this will cause a fitment issue or not, just that it is different than my OEM key.

For programming, I'd first check with a local independent European car service facility. I have a local shop with a Star machine which claims to be able to program keys for $30 the last time I inquired. This shop previously activated my fog light for me.

Again, thanks for the nice find... but the seller leaves me uneasy. :|

~toaster

 

[Niteshooter]

The one for my 2010 4 button reads 315 MHZ on my frequency counter. I suppose if you are curious and know someone who is an amateur radio operator or you have a shop that sells Ham gear in your area you can just putt on over and ask them to take a reading off your key....

 

[DreamCarOwner]

Toaster and Niteshooter, what great information you have provided. It has been a mystery as to the frequency of our FOBs. Now we all know the truth. I never thought of a freqency counter to "read" the key frequency, and I had no idea Toaster that there was a number inside the back shell of the FOB. Since I presently have only one FOB I treat it with kid gloves and place it on a velvet pillow every night to rest.lol. But I have opened it to replace the battery. I found I could not open my driver door with the key because the cable that connects the lock cylinder is worn in two. Apparently the previous owner unlocked the car alot with the key. Probably because he was down to ONE FOB! So I have another door lock assembly coming and hopefully can get my keys in order.
As to the wish,geek site, I was told it was a subsidiary of Amazon. I have bought alot of stuff from them. Alot of the same stuff can be found on Ebay, but each ad is from an individual in China. So the proces are usually fairly cheap and so is shipping. Most stuff comes in about 3 weeks, but some others take as much as 2 months in rare cases due to customs. My only bad experience was I ordered a cheap $2 128 GB micro USB card for my cell phone. I waited a month and no card. Then when you purchase from them they always send you an email asking if you have recieved your item. I said no so they gave me the choice to get a refund or wait for the item and they would re-ship it. So I waited another month and no item, so I emailed them and had a refund in a couple of hours. It was a calculated chance and I waited for 2 months for nothing, but they made it right with me so it's okay. Go to there search bar and type in "Smart Fortwo" and there is quite a bit of stuff to be had. I'm dying to order a set of the pedal covers for the gas, brake and footrest. I have the app on my phone and it occupies me shopping. So thanks again Toaster and Nightshooter.
Another great source of used smart parts is:

Autobahn Used SMART 451 PartsAutobahn Smart Car 451 Parts

I have used them and they are really good. I deal with a counter saleperson named Sean. Tell him Lonnie sent so from Smart Car of America and he will teat you right. They have good tested clean parts. I no longer use SpecializedGerman as I have had a bad dealing with them.

I would also like to personally thank JZCHEN for all his help and knowledge concerning Mercedes Benz, you are remarkable and I'm proud to call you friend ! Lonnie DCO

P.S. If you still have uneasy feelings about using the geeks site for a complete key, check out this one from Ebay:

http://www.ebay.com/itm/like/231461893592?dest=http://www.ebay.com/itm/231461893592

Better get them while they are still available. You can't beat the price compared to the dealer, but it is a question about quality and I will report on that when mine comes.

Here's an evaluation of the Wish site from the Amazon site.
https://www.amazon.com/ContextLogic-Inc-Wish-Shopping-Made/product-reviews/B00AEAVSKC

 

[heavyhauler451]

Thanks for the info. 315 it is... im gonna buy a few from ebay. And my buddy at work has a snap-on Ethos-Tech scantool that has key learn capability... as well as trans and clutch relearn....??.

the nice tthing with ebay.... you're protected. So the only risk is in finding a locksmith to cut the key properly.

 

[heavyhauler451]

Snap on ethos capabilities. Update 16.4

 

[cuhlik]

I bought a 315 MHz key from ebay and another key with a blade only, no electronics. I though I could have a key that didn't work as a remote, but at least would work in the locks.
Here's what happened.

The locksmith shop charged me $35 each to cut the keys and $40 to program the electronic key.
The keys go into the locks and turn, but the one without electronics does not unlock the car and does not start the car. When you put it in the ignition, the car displays a "bad key" image on the instrument panel.
The one with electronics works to mechanically unlock the car. And it works as a remote control to unlock the car. But it too does not start the car. Same "bad key" indication.
The locksmith has an instrument to read the key and he says my original key is 125 MHz. The documentation on the ebay page where I bought the key says 315 MHz.
One of the chips on the circuit board is different and one of the two antennas on the circuit board is different. This makes me think there are two circuits: one for the remote control and one transponder handshake with the car when the key is in the lock.
That latter one does not match or my locksmith does not have the knowledge or instrument to properly make the car recognize the key.
So, I'm out about $140 and still don't have a second key that can start the car.
I haven't found anyone who claims 125 MHz is a frequency associated with the Smart ForTwo keys.

 

[cuhlik]

Update:
I did a little research. This page wikipedia Smart_key is most useful, especially the part about Mercedes Keyless Go system wikipedia Smart_key#Keyless_Go
125 MHz is the frequency the car uses to query the key. The car has transmitting antennas in the door handles and in the center console where you insert the ignition key.
315 MHz is the frequency the car uses to reply in North America. In Europe, Japan, and Asia the reply frequency is 432.92 MHz. Some people call this 433 MHz.
If the key battery is dead or weak and the key is held close to the transmitting antenna (like by being inserted in the lock) then the 125 MHz signal is powerful enough to power the key enabling it to reply even with a dead battery.

My locksmith (Trask Mountain Lock and Key) did have a device to talk to the car over ODB2, and he did tell the car to recognize the two keys (original and new electronic keys) and the car does recognize both keys for unlocking the doors, but still only the original key works for starting the car. I think my locksmith doesn't know how to program the immobilizer which appears to be separate from the door unlock function.

 

[Niteshooter]

I had thought you needed to have a Mercedes Star computer to program a new key to the car's computer. Seems kind of odd that the key fob transmits on two fairly different frequencies though 125 MHz sounds more like a harmonic. Best way to know for sure is to read your key with a frequency counter. If you have someone who is an amateur radio operator there is a good chance they have a counter and would read your key or failing that if you have a local ham radio shop they will have one as well. Or just look for the car (without lights and sirens) that looks like an antenna farm and has a 'funny' license plate.

 

[cuhlik]

The locksmith had a key reader that claims the key is a 125 MHz key.
The documentation for the circuit board says 315 MHz.
The Internet says 125 MHz is the query frequency and 315 MHz is the reply frequency. So that's consistent with both the locksmith's reading and the documentation.
Too bad the engine disabler isn't happy with the programming.

 

[Foolios]

From the manual, button function;

What does locking and unlocking comfort functions mean?