Diamond Key Replacement - No Coding

[YYZ-M3]

As most people know, the OEM diamond key has a rechargeable battery soldered in place and the key body is glued together. Basically impossible to separate the halves without making it ugly or unusable.

I wanted new keys because one fob battery was completely dead and the other fob battery was weak. Rather than order new keys from the dealer (if you can still get them), I was able to Frankenstein two new aftermarket keys for about $100.

Parts required:

2 pre-cut diamond keys from fasterautokeys.com ($75 shipped). You send them a photo of your key and they cut it based on the photo.
2 Panasonic VL2020 batteries (90 degree) from Amazon or similar
2 BMW key roundels from your BMW dealer or Amazon

Cut open your original key fob (I put the fob in a vice and used an oscillating tool). Remove the circuit board.

Desolder the original battery and solder in your new VL2020.

Pop open the aftermarket key by prying it open at the blade end with the buttons facing up. Remove the circuit board and the transponder chip and toss in the garbage.

Place the original circuit board in the aftermarket key housing. It just sits in place (no glue).

Put the lid back on the aftermarket key and enjoy.


Left is OEM circuit board with integrated transponder chip. Right is aftermarket. Far right is the aftermarket transponder chip.

Edit: you can buy just the shell and save $10/key: https://fasterautokeys.com/products/...-bmw-1998-2010

Hope this helps someone. I bought the AK90 prepared to deal with programming the EWS and then skipped all that.

[Shonky]

Any reason you didn't buy the empty shell for $10 less?

[YYZ-M3]

I didn’t know what to expect when I started. My original plan was to code the new aftermarket keys.

[Shonky]

Fair enough.

[sapote]

Put the lid back on the aftermarket key and enjoy..

I found the after market board was rocking inside the closed case and this caused the remote switches not functioning reliably. Does the stock board sit well in the new case?

[YYZ-M3]

I haven’t had any issues but the car is parked for winter so I have only used the keys a few times.

[Schiffi]

But don't go with the cheap aftermarket china Transponder. You won't be happy with it for a long time. The first time they work properly, then they get cracked. Had already several of these china Tramsponders. Look for a original NXP Transponder.