I recently used a valet parking service at a hospital. After visit car arrived and off I went. Made one stop. Got the no key detected alert. Started with fob on button and went home. The batteries in the fob are pretty new. was starting to investigate and then remembered fob low power mode. You can enter the mode with a few pushes on the fob lock button. It's in the book. Anyway I suspect the valet gave the lock button enough hits to enter low power. Same pattern of pushes gets fob back to full power. I'm too old to be tested like this.