[starfox5194]

Hey guys,

I saw a youtube video on how to upgrade an F series key fob to a G series here:

Also, another company - gates innovations will do this service for you for E series to G series key fob... for a price. I decided to test my luck and do it myself.

This is the fob you want -
https://www.aliexpress.us/item/22518...andl_shipto=US

KEYECU 315 / 868 MHz PCF7953 Chip CAS3 System Keyless-Go Function Upgraded Remote Key Fob for BMW 3/5series x5 x6 KR55WK491

NOTE THAT THE KEY SAYS ***CAS3*** There are tons of other keys for CAS4. I tried them, they don't work. IDK why. Only buy if it says CAS3.
Also, make sure you are using the correct frequency. USA is commonly 315 mhz. It is written on the back of your E series fob.

Key works perfectly for me. ****You need a comfort access key**** for this to work - the G series key does not fit in the slot.

I actually think the G series fob has better range than the E series one haha. Comfort access door handles work better. Can unlock from further away. And the key feels much more premium.

I used a cheap hot air station from ali-express. Set it to 350, applied flux, held the chip with some tweezers, and waited for it to pop off the pcb. Repeat for the second board. Then I lined up the chip on the new board and used hot air to re-solder the chip. Worked on the first try. Make sure you have plenty of light and some steady hands. Honestly if you can solder, you should be able to do this.

Some notes:
1 - I wrapped the board in kapton tape to protect other ICs and the buttons. I still ended up damaging the buttons due to too much heat exposure. They are not as "clicky". I got some donor buttons from another board and used those. They work great.

2 - The G series keyblade will have to be cut. I was able to get this style blade to unlock the door, but not lock it. The g series blade is thinner than the E series, so that's probably why.

If you don't want to do all this hacking, you might be able to get a locksmith to program that CAS3 g series key fob to your e90. No promises though.

Hope that answers some questions for anyone else who might be interested.

[Drifter2090]

Great write up! So you didn't apply new solder to the chip? Just hot air to melt the existing solder?