I just got a 2014 and I had a few questions. The key fob worked fine but after a week sitting in the garage the car won't recognize the fob. It keeps asking me to hold the fob up to the push start switch before it recognizes the key.
Also when I exit the car and hit the lock button I can't hear any locks set.
Is this the sign of a low battery?

 

Maybe but just change the remote battery and go from there. It's the simplest and most cost effective thing to try first. Also check the voltage on the car battery to confirm it's healthy. Low batteries in these cars can cuse all kind of strange things to happen.

 

I believe the symptoms you are describing are those of a fob with a low battery. I would replace battery and retry..

 

That's what I suspect. I drove with the key fob and cell phone in my cupholder. Apparently when they are that close the cell phone will cause the fob to drain the battery. Who knew

 

I have a carrying bag for my laptop and inside I also have my cell phone and Lexus cell fob quite close to each other.

I never considered one would drain the battery of the other. How does this happen, technically speaking, that the Iphone drains the fob battery?

Isn't it more likely that your 2014 battery fob, being four to five years old simply needed replacement instead of being drained by a phone?

 

If the key fob battery is low, you shoud get a message on the dash every time you turn off the ignition. I'd still change the battery in the key, though as the symptoms suggest this as the cause.

 

I was googling around and found a page from a lexus dealership that mentioned issues with key fobs.
it said
What to do if your battery seems to die frequently: Lexus key fob batteries should last between one and two years, so if your key fob is getting weak after just a few months, chances are your smartphone is the culprit. Explains one LTS: “Your phone can actually drain your Lexus fob battery—there’s a transponder inside your fob that can respond to phone circuitry. As a practice, keep your fob away from your phone at home or work, and keep these items in separate pockets when you’re out and about.”

 

The message on the dash is that it doesn't recognize the key and to hold the fob to the starter button while depressing the brake.