Low tire light came on - tire pressure ok

That is the low tire pressure warning. It can come on for several reasons. It commonly comes on in the fall as temperatures drop, the air in the tires contracts and the pressure drops. Check the air pressure and fill as needed. The tires also all need to be within 4 psi of each other.
Another common cause is that one or more tire sensor needs the battery replaced. This is not generally considered a DYI project because for most cars the tires must be removed from the rims. Finally the sensor can be damaged by hitting a curb or by adding chemicals into the tire used to seal small leaks.
As long as you check your tires visually prior to driving it is usually ok to wait to service the sensor for when you replace or rotate your tires.

Please keep in mind driving on a tire with low pressure can damage the tire, the rim or even cause delamination of the tread and cause an accident. The Firestone recall that involved Ford Explorers several years ago was from driving on tires with low pressure.

bad sending unit in one of more of the tires , or needs to be reset, BUT as long as tire pressure is good its fine ,I would never tell someone to do something that would even slightly endanger them . but make a point to have it looked at.
Woody

After checking/adjusting all tire's pressure (including spare, some spares have a tire pressure sending unit), turn ignition "ON" (NOT "START", just the position key is at when you are driving).
Press the MODE button until LOW TIRE PRESSURE HOLD SET TO RESET is displayed.
Press and hold the SET button until a chime sounds and TIRE PRESSURE RESET is displayed and a chime sounds 3 times.
Release the SET button and TIRE PRESSURE NORMAL is displayed.

You will need the dealer to scan the system for the problem that giving you a false indication of low pressure. Also make sure the spare has the correct pressure.

Air pressure in the tires drops when it is cold (as much a 5 PSI), as you drive they heat up and that makes them fall within the correct pressure limits to turn off the low tire pressure warning. I suggest you get an accurate tire gauge and air your tires up to 32 PSI all around.

This (!) symbol is your TIRE PRESSURE MONITORING SYSTEM (TPMS) warning light.
The manual has this to say about it:
This system monitors tire pressure. if the low tire pressure warning light illuminates, check the tire pressure in all four tires. Adjust the low tire pressure to the recommended cold tire pressure shown on the Tire and Loading information label located in the driver's door opening. After tire pressures are adjusted, the vehicle will need to be driven at speeds above 16 MPH (25 km/h) to activate the TPMS and turn off the low tire pressure warning light.

make sure that you have 36psi of pressure in ALL 4 TIRES. then drive vehicle for about 2 miles or less at at least 35mph and if all is ok,(sensors are ok) than the light will go out by it self.

try resetting tire pressure monitoring system

have the pressure sensor replaced

Some newer Toyota vehicles have a sensor in the spare tire. Tires loose air over time naturally. I would check out the spare.
When did this TPS light start coming on?
Have you had new tires put on, or had a flat repair done before the light?