Starting/Driving without the key present

[B6pilot]

I have a 2015 M5, purchased 3 years ago CPO'd from a dealer. Last night, I ran to pick up some food and when I got to the restaurant (6mi from my house), I turned off the car. When I opened the door, I realized I didn't have the key as I had left it on my desk and forgot to grab it. I remember reading that sometimes the car will start if the key is "close enough" to the car.

Thinking I had just stranded myself, I did a full search of the car just to make sure I had really forgotten it. No sign. Just for the heck of it I tried starting the car and it fired right up. I didn't want to leave a car that could start without the key, unlocked in a parking lot, so I drove back home to verify both keys were in the house, which they were. So, I am a bit perplexed as to what happened.

I grabbed one of the keys, went back to the restaurant and picked up my food. With the key, the car locks, arms, and will not unlock if I don't have the key on me. Comfort access works as it should, and all appears otherwise normal.

When I got home, I left the car unlocked while I placed both keys in a faraday cage inside my safe and went and tried starting the car. It started right up again! No iDrive warnings showing the key was not inside the car. What could allowing a complete bypass of the key bring present in order to start the car?

[JayDD007]

I’ve seen people lose keys in cars (slid into the floor vent under a front seat typically) then they’d just purchase a new one. Since the old key is still “in the car” it will start but also lock and unlock.

The dealer can also block keys so besides the two you have and want to use the car won’t recognize others anymore.

Hope this helps

[B6pilot]

Originally Posted by JayDD007

I’ve seen people lose keys in cars (slid into the floor vent under a front seat typically) then they’d just purchase a new one. Since the old key is still “in the car” it will start but also lock and unlock.

The dealer can also block keys so besides the two you have and want to use the car won’t recognize others anymore.

Hope this helps

And this is exactly what happened. Found the key deep in the no man's land trench between the passenger seat and center console. Whew!