2014 Tacoma has a strange beeping alarm coming from the center of the dash

This started up a few days ago. After the truck runs for about 15 minutes, a short beep starts sounding at a two-second interval. It's not the normal one, like the seat belt chime, that comes from over near the steering wheel. The sound continues even after the truck is shut off for probably more than an hour or more. There are no other unusual lights or sounds other than that. When the truck is locked, the alarm light (red, vehicle silhouette with key overlay) flashes every two seconds as normal.
What is that thing? Neither the manuals nor Google seem to have heard of it. Any help at all would be greatly appreciated.

 

Does it have a manual transmission? If yes, is this the same sounding beep as when you shift to reverse (I get that it’s a recurring beep), or different?

 

Watching out of interesting to see the outcome.

 

If the sound is coming from the center of the dash: is it the same beep as when 4HI or 4LO isn’t fully engaged? It seems like that beep is at about the same 2 second interval, but usually there is a flashing green indicator light in the gauge cluster.

 

Hey, all, thanks for the help. @BigSkyTR6 gave me a great hint. Got it resolved. It's an automatic transmission, btw, that has only seen 60k miles and isn't normally used in 4wd mode.
Here's the deal: the alarm was indeed the one that flashes and beeps when the selector is set to 4L but the 4H to 4L transition hasn't yet completed. But - the light wasn't flashing and the selector had, as far as I know, not moved out of 2H. The beep also wasn't really at full volume either. Anyway, just for the heck of it, I cycled to 4H, then to 4L, then back to 4H, back to 2H and POOF - no more beeping. My theory is that (I'm not the only driver of this truck) the switch was turned accidentally a little bit or maybe bumped into and not everything stayed in synch. A somewhat uncharitable F-150 owner I know theorized that maybe 2H was trying to identify as 4L but couldn't beep loudly enough or make its light flash. I told him to watch his mouth around my Tacoma. I think my theory is a little more likely. This weekend I plan to check all the fluid levels then find some gravel and put the transmission through all of its paces. If I find out anything else I'll check back in.

 

Fantastic!

Glad you got it figured out.

 

While your under there check the vent hoses on the 4wd actuators, if they are cracked or disconnected replace them as water and dirt will get in the actuators and destroy them.
https://www.tacomaworld.com/threads/4wd-system-operation-help-thread.742420/

 

Does anyone else ever drive your truck?
I might know a guy that got the fan speed and 4WD buttons mixed up.

Why the hell did Toyota make the switches “look” the same?