2015 Platinum AWD 69,000 miles.
Went to a store this evening and after turning the car off I realized as I was getting out there was still music playing. Got back in and checked a few things, car was in park, light on the start button was off etc. Started the car, the radio turned off then went through its start up animation and turned on again. Turned the car off, same thing radio stayed on. Probably did that 5 times, even tried remote starting. When I remote started it the car would not turn off when I held the brake peddle down as it should. Everything to do with the radio / infotainment system works can go through all the satellite radio stations, listen to music on USB, search for places on the Navigation etc but everything else like the AC, auto headlights, gauge cluster are all off. The shift interlock and steering wheel lock are both activated.
Only thing of note on the drive to the store was I had to abruptly stop when a car pulled out in front of me then stopped across my lane when they saw me coming, genius move on their part. I would hope that sudden stop wouldn’t cause damage to something though. Nothing on the vehicle has been changed other than oil and rear brakes in the last 9,000 miles or so.
The local dealers all closed in 10 minutes so I called one and asked if they had any recommendations to check or try. Service advisor that answered the phone claimed he had never heard of any cars doing this. All he could recommend was disconnecting the battery for a while. Luckily I carry a decent toolset with me so I got the socket wrench and disconnected the battery. Wandered around the store for almost an hour before coming back.
Soon as I reconnected the battery the radio came back on. Tried driving around a while, even made a few intentional abrupt stops (with no one behind me of course) to see if that would undo anything. Stopped in a parking lot and turned the car off, same thing. Even tried turning the car off in neutral and restarting just to try something else. All the dealers here were closed at that point so I called one in TX. They were open but technicians had all gone home. The service advisor also had not heard of the problem. Tried 2 dealers in California. Same thing, never heard of it, no one still there that works on cars. One did suggest it could be the engine start switch.
Radio on, car off
Nav still works.
Currently sitting in a coffee shop with the battery disconnected again so the battery does not die while I research this and look at the service manual. Looks like the engine start switch is $40 and specific to the 15-18 MY, was hopping I could snag one at the local junkyard for $8 just to try it but they don’t have any Muranos that new. Don’t really think that will fix it though.
Anyone else ever had this problem? Would much rather find the problem and fix it myself than disconnect the battery every time I park it before I can take to the dealer.