I am following guide to install the OEM Audio+ speakers and one of the first steps is to disconnect the battery - am I going to have any issues doing this? Anything in the infotainment or other sensors going to trigger/get reset as a result?

No issues. I disconnected mine a few times and never noticed anything.

I've had the ground strap off of my wife's 2014 4R a number of times.

The first time you start the vehicle after reconnecting ground, the engine may stumble on first start attempt. Normal.

Mine always fires right up after the 2nd try.

You may need to resync your windows after disconnecting the battery. Not hard at all to do. Search around here for a how-to.

You may need to re-set your your power windows.

How To Fix 4runner Automatic Windows After Replacing Battery - YouTube

I disconnected my battery and and spent a week chasing gremlins until I did the reset.

That's... an interesting gotcha! Looks straightforward enough and good to know if it ends up happening to me

If you want to watch the YT video - fine, but fast-forward 3 mins into it - skip all of the useless gibberish up front.

Here's a text write-up I put on an Avalon section at toyotanation.com awhile back. Pretty much the same across all models as far as I can tell. Worked on the wifes '14 4R and my '15 Tacoma.


Anytime the battery terminal has been disconnected, please initialize the driver’s door
power window and front passenger’s door power window after reconnecting the
battery terminal.

With ignition switch in the “ON” position, do the following:

1. Push down and hold the driver’s door power window switch to completely open
the window.
2. Pull and hold up the driver’s door power window switch until the window closes.
Continue holding the switch for approximately one second until the switch changes
from blinking to a constant illumination.
3. Check for proper operation of the “one–touch open and close” function by fully
pushing the switch briefly to the “DOWN” and “UP” positions.

At this time the power window switch for the passenger’s door window should
be blinking.
4. Push down and hold the passenger’s door power window switch to completely open
the window.
5. Pull and hold up the passenger’s door power window switch until the window closes.
Continue holding the switch for approximately one second until the switch changes
from blinking to a constant illumination.
6. Check for proper operation of the “one–touch open and close” function by fully
pushing the switch briefly to the “DOWN” and “UP” positions.

Sunroof initialization is similar.