What year? Most valet keys that I have seen are shorter than the master key and allow you to start the car but not access the trunk or glove box. I would assume that in a modern car there maybe a chip involved in this process as well.
Make sure you are using the Master (black head) key, not the Valet (green head) key.
Use the black key that you have to open the truck, it overrides the Valet Mode. The key goes in a hole that is between the X and the K on the enblem on the rear of the car.
pry it open with a crowbar
Valet mode disables the electric trunk release and the "home link functions" for security reasons when valet parking. The "valet key" will not open the trunk
Normally the difference between a Valet and Master key is the Valet key will not work in the glove box or trunk of the vehicle. The actual differences in the keys are either the grooves in the key or the thickness of the key which restrict it from going into the locks. Occasionally the valet key may not have certain cuts on it to work those locks.
Unlock the driver's door using the BLACK key (not the green one).
What do you mean by "valet mode"? If you mean the trunk release button won't work, there's a valet switch inside the glove compartment that activates and deactivates it. Just turn it off. OR You use the black key in the trunk keyhole which is located in the xk8 emblem. The Keyhole is located between the x and k. That should take it of valet mode.
It sounds like you only have a "valet key" My valet key is green. The main key is black. The valet key will not open the trunk or the glovebox. If you do not have a main key you should be able to get one from a dealer using the VIN #
I hit the valet swtch in my 1995 xj6 when cleaning, The boot will open via the switch on the dash and or with my key, but when using the fob to open the car, all is fine but the boot has to be done via key as it dont via central looking.
Its a valet key because it does not allow access to the trunk and glove box.
You are problay using the valet key. We had the same problem when we fist got our van. There is another key that work right. Get it.
On most cars, the alarm is deactivated when the right key is put in the ignition