Hello all,
This is my first post, and I'm sorry to have to introduce myself out of necessity. In early February, I was rear ended and my beloved 2014 Audi Q5 TDI was totaled. I replaced it with a new 2014 Cayenne V6 platinum edition. I've been absolutely in love with the car over the 1500 miles that I've accumulated.
Today, however, I had a big problem. I was exiting the highway into a rest area, when at about 25-30 mph the engine completely cut out. I had no power steering and the brakes didnt appear to be working. I stopped, waved people past me, and restarted the car. Everything was normal. No warning lights, not a thing. I continued my trip of 90 miles and the car ran normally the entire way.
However, I'm now paranoid about driving the thing! I need it to get around, but I sometimes have my 2 year old niece in the car and if that had happened while making a left turn against traffic rather than on an off ramp I don't even want to consider the possibilities of what could happen.
I did a quick search of the forum and didn't find any similar experiences, but forgive me if I missed something.
Any and all help is appreciated!

 

Any codes or warnings pop up on the display screen? If I was you I would bring it into the service department and explain the situation, maybe it set some "soft" body control codes that might pinpoint an issue. Worth the time to quickly look it over before a possible reoccurrence happens. The brakes would be much harder to press due to having no assist, should still stop it, just scare the crap outta you when it would happen lol.

 

When the engine first quit, every warning light on the dash seemed to come on. When I turned the car back on, no lights and everything was fine.
The brakes may have been working, but just barely! Between that and the power steering going out, I felt like the next step was to crank the engine manually to start like a Model T
In all seriousness, I love the car but if this happens again it may be the shortest period of time I've ever owned a car. Dealership said they'd be in touch tomorrow..

 

A similar thing happened to me on 2 different occasions, with 2 seperate vehicles. (Neither of them being my Cayenne, though).
The 1st occasion it turned out to be a loose battery connection on the ground terminal.
The second was a corroded wire under the hood. I think it may have been to the fuse box, or the ecu, or the fuel pump. It was several years ago, I don't remember exactly.

Hopefully your issue is something similar and not a major problem or something that lowers your confidence while driving your Porsche.

 

This is probably a stupid question, but when you take it in for service they might ask you the same. There isn't any chance you accidentally bumped the key (or "key" if the platinum comes with keyless entry and drive) right?

I agree with the most likely option being a loose electrical connection. Did you buy the car new or used? Still under warranty?