jfort

Are you sure the dealer had the blade ground according to the VIN? I've replaced several Cayenne keys by purchasing from a dealer with no problem. The fob electronics will work, but the blade and door receptacle are mechanical. Also, you are right. Not wise to leave car unlocked. It doesn't go to sleep like a locked car and drains the battery more quickly, compounding the problem.

ADias

His key works in the ignition and glovebox. I think that what he's saying is that the car is locked, went into hibernation and his (proper) key does not rotate the door locking cylinder. Locks go bad, get frozen, if unused. It is a good idea to operate the door lock with the key periodically. I would use some WD40 or equivalent and try moving the key gently. This may take several attempts.

Iceter

DesmoSD

Ah, that's right.

You have the key fob so as long as that works, you should be able to get around to locking and unlocking your car. So even when you unlock it with the key fob, you still can't lock it with the key?

Perhaps, try some WD-40 in the slot to see that might free it up.

Castor Troy

Going to try WD-40...the suspense is killing you i'm sure..

ADias

You should try to push some WD40 around the rotating barrel. Give it a few tries. Once free, wait a while (days) and squirt in there some LPS or equivalent.

Lance Tran

Sometimes, dealerships will with-hold the spare key. Most will do it when the vehicle is being financed outside of Porsche Financial service. This is typical of smaller dealerships.
Car key replacement in London might be able to program new Fob to car, if they have a security level license; you need to call, ask, price shop.

8x57IRS

I would urgently follow Petza's recommendation for a dry lubricant like grafit. Liquids like WD-40 accumulate dust and dirt and make the problem worse. Unfortunately, the recommendation persists.
I also think it is a mechanical problem.
When the car is in sleep mode, pulling the door handle is enough to wake it up; then the key will work. No need for mechanical unlock.

Petza914

There are also hybrid Dry lubricants Blaster Dry Lube is one of my favorites. It's a Teflon suspended in a carrier solution so it sprays like an aerosol lubricant but once the carrier solution evaporates away, all that's left is the dry Teflon.