Comfort Access Replacement Key
 

The pre-owned 335i 'vert I bought came with only one key, I went to a $tealer to enquire about a replacement and the price they quoted almost knocked me off balance. $300 + tax for the key + 100 bucks to program it, almost $500 for a replacement key.

I inquired with morristownbmw which sells stuff on eBay and they informed me that they don't sell the keys on the web due to new BMW policy. They need a copy of photo id. + title.

Do I have any other options.

Thanks

Nope. BMW controls all the keys and you really have no choice.

How about a valet key, as a temporary 'back up'?

That could work but the valet key is plastic and there are no Comfort access or even remote features with that. I would not be using that plastic key anymore than I have to.

I paid a little over $200 (I think it was $230) for mine with programming but I don't have comfort access. That being said, I can't imagine comfort access doubling the price. :dunno:

For the Non Comfort Access keys, I believe that using the old way of using the original key and they the new key which will be initialized. For Comfort Access keys, the car has to be programed to
1) remove the old key from the system so that it will no longer be recognized(since you don't have the key)
2) Program the car to recognize the new key. Since the comfort access has to "listen" or sense the key, the car has to be told what key it is to look for. If you don't tell the computer to learn the key then the CA will not work. I have two BMW's with comfort access so when both my wife and I are in the car at the same time, there are 4 CA keys present and the car has to know which keys to sense and what keys to ignore. That programming requires hooking the car up to a computer which you don't have to do with non CA keys

The only option I could think of is to look for a cheap used key (ebay, etc.), then order separatelly the metal key part (shouldn't be more than $30-40 from dealer) and pay for programming. I don't know if BMW comfort access key is visually different from non-comfort (MINI comfort key has removable battery cover vs. sealed on non-comfort), which could help as the part #s on used keys may be worn out/unreadable.

How long is a reasonable time for a key(non-CA) to operate before needing the battery replaced?

My wifes key died last week and the dealer tried to tell me it was because she didnt drive enough. She drives it once or twice a week. The car is 18 months old. I feel that is ridiculous.

It's the same for Mercedes too. A friend lost her husband's key to his 2003 E500. No Keyless Go (Comfort Access). It was over $200 just for the key. They needed ID, vehicle registration...and it took like 3-5 days to get it!

For non CA keys, you cannot replace the batter, you will have to replace the entire key. As for the longevity, driving the car 1-2 times a week should be more than enough to keep the key charged. My wife drives my car about 1-2 a month and her key has never had a charging issue.

YOU CAN REPLACE BATTERY in Non CA keys!!!!
 

Alot easier than you might think dealer and even good Indy mechanics will tell you it cannot be done, I do it at $50 a pop for friends and people who dont want to buy another key you just need an EXACTO knife and a glue gun and you basically separate the front of the key from the back of the key pop in a new Watch battery CR 2025 I think and glue gun it back together NEATLY!!!
looks good as new just saved yourself a fortune. Good luck and cut carefully dont hit the circuit board too hard or you might cut off a transistor :-)
*This is for informational purposes only, I am not responsible for any keys that dont work if tampered with*:dunno:

Yes it can be done

So you replace a rechargeable battery with a non-rechargeable one and that does not cause any issues when you use the key? To me that sounds like a bad idea. If you replace it with a rechargeable then I am sure you can do it then

REPLACING BATTERY IN NON CA KEYS
 

I wasnt going to elaborate too much on this because I dont want readers blaming me if it doesnt work or they break their keys, I figure if your at the stage of considering it then your about to spend $200 on a new key anyways and that old one will just be a backup.
Ok kids, yes the factory key is a rechargeable watch battery, I use a Li-Ion 3V replacement Duracell, Energizer etc.. I am assuming due to lack of any complaints from keys I have done that the battery has a long life 3V is actually pretty powerful for what the power draw from the key is. I dont know how long they will last maybe a 1 year to a few years there are 2 pieces of metal soldered to the factory battery + and - sides that you have to break and re attach to the new battery, but you have to break it carefully from the old battery dont break it into pieces! The hardest part really is just cutting the plastic with a very sharp razor, slowly scrape away at the seam all the way around the key other than that its pretty straight forward make sure you put the new batter exactly the same way the old one was with those metal plates facing the exact same way as before, take a picture with your phone before you start breaking things :stickpoke
Good luck I just save you all hundreds of dollars please send all donations to me!:rofl:
Or Pm me if you really dont want to do it, other than that dont forget to RE INITIALIZE YOUR KEY TADA:popcorn:

I just did a little research and according to SONY the power draw of the keyless entry systems is similar to that of a PC motherboard so lifespan will vary but could be several years, Im guessing the amount of recharge the cars ignition provides is minimal at best so perhaps that drip charge is possible with all coin batteries, pure speculation on my part havent confirmed anything, maybe someone in here with a more technical background can get down to the details and figure it all out.