Get a paper buisness card, a toothe pick (plastic or wood), and/or any other thin, flexible, but sturdy object (I found credit cards to be too thick for this, also make sure your "tool" will not scratch the screen) and press the tool between the physical touch screen glass and the plastic bezel that surrounds it (you only need to get it about 2~3mm under the bezel). Using the tool under the bezel, slowly and carefully work your way from one corner to the other (do take the tool out and clean it of debris frequently, the corners are tricky) in a pulling/pushing motion; the key here is to try and get any debris that may have worked it's way between the bezel and the screen out as just that slight pressure can trick the touch screen into thinking it's being pressed. After you've cleaned the bezel, I'd use a micro fiber, clean cotton, or soft paper towel and some lens/glass clean on the cloth to wipe down the touch screen.
If the issue persists after you've attempted the above (I'd try it at least twice to make sure you didn't miss anything...) you can try and see what part of the screen is not functioning correctly. To do this you need to enter Diagnostic Mode on the head unit.
Diagnostic Mode:
-Ignition "Key On," not Accessory (Engine Running or Not, it does not matter)
-Press and Hold the "Info" (on some head units it will be the "Apps" button)
-While Holding the "Info" (or "Apps" if equipped) button, cycle the headlight switch from "Off" to "On" 3 Times (Off -> On -> Off -> On -> Off -> On -> Off)
The head unit should enter a very simple looking interface with some options (if not repeat the process again), select "Function Check/Setting" from the menu. Once you've entered that sub-menu you should see "TouchScreen Switch," select that and it will bring you to a testing screen. Press anywhere on the touchscreen, there should be a " + " symbol where the touchscreen registered your touch (this symbol will stay in place until you touch the screen again); this will give you an idea of where the touch screen thinks you're pressing and/or if it is even registering your touches properly (this is not a calibration, it is merely diagnostic.)
To exit "Diagnostic Mode," just cycle the ignition.
If you find that there is a dead spot and/or the touchscreen is just not registering your touches properly, the final thing you can try is to disconnect the battery for at least 15 minutes (make sure you let the vehicle relearn idle properly after you start it by letting it just sit and idle with no loads such as headlights, A/C, ect. turned on for at least 5-10 minutes.) This should force the headunit to boot up from ROM memory (essentially you're forcing the hardware to revert to factory default software.) If this does not fix the issue, you will need a new head unit and/or send your head unit out to a professional audio company that rebuilds/repairs factory head units. The reason for this is because the 2010 & 2011 4Runner models came with non-Entune headunits that cannot be updated via the typical USB drive we use at the dealership; 2012+ models do allow for software reflashing.
I hope the above information helps you out.
