Frequency depends on manufacture date and vehicle market. Everything for the American market prior to 06/2014 is 315mhz. After that date, it's 434mhz. Most of Europe is 434mhz, and some Asian market is 868mhz. I use unlocked OEM keys as much as possible, and the frequency cannot be changed on a factory key. In general, you need to buy the correct frequency keys. A few Chinese key designs can be set to different frequencies. While it is possible to change the frequency that a vehicle is designed to receive, this will cause the current keys to no longer work with the vehicle, and will mean that keys cannot be ordered from the dealer anymore.