In case your smart key broke
 

So my smart key broke (on the key fob). Going back to the original key was fine, but it's a bit too long & big (revised style came out in year 2001 or later, I think).

I manage to buy a used smart key, play around with it enough to switch out the board & chip, and YAHHOOOO, it works on my car (both window/door, and start engine).

Save myself at least $150 for a new key, and one life time of the key (you can replace key only 8 times for a car, dealer confirmed).

Cool! very useful information! :y :y :y

smart key
 

8 on rail one, there are 3 rails. You are correct the smart keys on E-bay are usefull for only cases.
Mine broke the dealer tried not to use a slot, ordered a direct replacement, someone screwed up and it disabled the second one. They took the car in and ordered another as a "additional",everything fine. The person who designed this should be in the space program, keys are coded by the factory and the remote has to talk to the system to program itself (20 min to turn) (20 to start) to unlock the ignition, but will work on the doors out of the box. If the system is replaced it ships with a coding key (and new remotes), that has to be returned to the factory.
The technical theory takes eight pages...
PS to get to the "batteries" pull out the hard key, push the little gray bar inside the opening, and slide the board out of the housing.

Wait so you mean the LARGE smartkey chip/board can fit into the Small smartkey? So I could take one of my LARGE smartkeys and get a small one on ebay and do a swap?

ZAM,

I thought your car had a switch blade key? no? :nix:

Please clarify.

OV

Mine is a 98. From 98 on, the W210 use smartkey.

So which chip is pulled and replaced?....since I'm concluding that the circuit board from the older/larger unit isn't going to be shoehorned into the smaller, newer case.

I'll send along the old key so that you could try it out.

There's only one chip: the whole board.

Instruktions please , so will the board from the older casing fit the small casing.
Thanx,

Nice.

I purchased a used old style key on eBay to replace a cracked key. I found it is very easy to pull the old circuit board out of the old key and slide it into the new key. $19 plus $6 shipping is certainly a lot cheaper than $150 replacement keys.

Jim

My dealer said it would be about $250 for a key so the $150 for other dealers sounds about right.

yes no?

Based on the size and shape of the board in the old key, I don't see how the old board would fit in the new key. I am not about to pull the new key from my 03 W211 apart yet to see if the chips look similar.

Jim

you could just buy the smaller key to replace the old bigger one. my dad thought he lost his... so he got one of the newer smaller ones... looks so much better

Hi Zam2000

How do you pull the chip out? Is it just a straight pull using a plier from the battery opening?
I did want to damage the chip as it seems to be so tight inside the key cover.

Thanks,
Jeffrey

Jeffery,

I'll respond. After you take the end of the key off and remove the batteries, there was a little white plastic keeper "bar" across the circuit board. I removed that with a dental pick. The circuit board will then slide out. It was easiest to perform this surgery on the "new" key since my old one was still working. With my new surgical confidence, I then removed the board from the old working key and rebuilt the new key with the old board and white plastic keeper bar.

LOL, do you still have the 2k1+ keys from your old cah?

Thanks JimPurdy, I'll give it a shot later.
Regards,

Question about a found Smart Key
 

When I purchased my 2001 E320, it came with one Smart Key. However, when I took it to get cleaned up and washed, the guys found a second Smart Key inside the car.

It will lock and unlock the doors and operate the doors/sunroof mode. But it will not unlock the ignition or turn to start the car. I have read posts that mention that the car must "program" the key. Can someone give me detailed instructions on how the process works?

Blair

Smart Key
 

Number one, look at the first post, slide the little gray release and the board will slide out of the housing (just like a battery change). You can replace the housing but the electronics will not work since it has to be coded to the car.
Two: you will not be able to use the board from the smaller one in the larger one. I immagine you could order the new? style but there is no reason to since the key does not wear out.
Three: if the remote you found under the seat unlocks the car it might be the correct one, but if the dealer ordered a replacement instead of an additional one the replacement will invalidate the one being replaced. I know, my dealer ordered the wrong one and it took my other remote out of service forever.
Four: these remotes are infrared and electronic and neeed to transmit their code to the car which sometimes takes 45 minutes. They light up, awile later they turn but the engine will not keep running and finally work.
The only value those remotes on E-Bay are is for housing replacements, yes they work but not on your car. Parking attendants were good for looking in glove compartments, since some people kept the extra remote there with the owners manual, rental cars were a good source since they always stashed the manual and the remotes behind the trunk liner (when the car was sold they were new)

I got the newer smaller smartkey, and tried to make my old key into it, or make the swap the chip.
But, it seems not an easy job. The whole board will not fit, and the chips look different in size.
Anyone has idea? Thanks!

Hi, Zam,

Did you mean you have two different keys, and you replaced the housing of the small one?

Ben

I tried it too, the bigger smartkey board will not fit into the smaller smartkey.

hey guys I have the S-class like square smart key with only one button which is kinda annoying. Is there any way I can use reprogram one of these smart keys for my car??