Get the 12v battery tested, disconnected from the car. All my gremlins I have traced to a weak 12v by using a battery voltage recorder, while not getting any 12v low dash warnings. It probably worked later because after you wake the car it recharged the 12v. It gets worse the colder it gets.

 

That's the classic weak 12V battery. A failing one causes those exact random electrical scares, especially in cool weather. Get it tested. It's the most common cause.

 

So now I'm wondering if a weak 12V battery might've been the cause of the gremlin I experienced over the weekend with my 2023 AWD Pro S (16,300 miles).

I got the dashboard message, "Key Fob not detected. Please hold key on designated surface." I guessed (or remembered reading somewhere) that the "designated surface" was in the cupholder, so I put the fob there -- and voila!

No problems have occurred since. So now I'm waiting for another shoe to drop.

 

I got the dashboard message, "Key Fob not detected. Please hold key on designated surface."

Replace your FOB battery, or learn how to use the emergency key in the FOB to get in your car. Both of my FOB batteries needed replaced at 2 years old. That message would not be caused by the 12v.

 

Gremlins also read this thread?

 

I had taken my 2022 Pro S AWD in for the battery cell recall….they ran a diagnostic and found they had to replace a few cells. They did the job in less than a week when I was scheduled to be out of town.

About a month later I had the issue the poster described. I got the red warning lights and message when I arrived at work one morning. When I left work I had a yellow check electrical system message. I drove it straight to the dealership. By the time they went to look at the car, there was no warning, but I had at least taken a picture of the yellow warning message and described what happened with the red earlier in the day. They took the car in and gave me a loaner. It took some time for them to check it, but they found more faulty cells. It took a few weeks for them to get the replacements in and installed. Fortunately I was able to keep the loaner.

That was over a year ago….fortunately I haven’t had any further issues. My light just came on for my 40K service check. Hopefully all is good.