[HoodPin]

The electronic function can drop for a variety of reasons. But hard to believe the manual key function suddenly stopped working. Even if the battery is dead, the manual key function should still work on the driver's door.

If the key is turning in the cylinder, then something has broken in the door's hardware, and the lock cylinder is no longer correctly controlling the rest of the mechanism.

If the key is not turning in the lock cylinder, then there may be a possibility that someone has tampered with lock, maybe trying to pick it to break in. If damaged internally, the key may no longer be interfacing correctly with the cylinder.

It's not the wrong key, is it?

The only other thing I've ever heard of is a bizarre alarm feature on some Range Rovers. If the vehicle detection system thought there was a break-in in progress, it would completely lock down the entire vehicle, so that nothing work or unlocks. And apparently, only the dealer can reverse. But I doubt the Cayman is so equipped.