I have 2010 Kia Optima. Just got new tires on 2 weeks ago. On my trip I got a flat and went back to Firestone. They put a new tire on and my TPMS light has been on ever since. 4 days now. The scanned and said all sensors are working fine. What do I do?

You need to reset the system with the new inflation pressures. Look in your owners manual for instructions on how to reset TPMS

Here are some opinions.
My daughter's car has 2 tires saying "flat", and they aren't.
First time this happened, dealer charged $100 to turn the light off, the computer needed to be reset.
Resetting the computer is what is needed, unless your wheel sensor has stopped sending a signal ( unlikely).
Since the product has been available on the market for 7 years, now you can go to some garages and tire stores and they will turn off the light for you.
Watch out for "hustlers" who want to sell you who knows what.
Call some stores (Goodyear, Firestone) and see what they say.

If you look in your manual, there is usually a procedure for resetting TPMS sensors. They can be as silly as turning off and on the headlights 3 times or honking the horn with the key turned to the on position. If you can't find it in there the dealer will have a tool to reset it for you.

TPMS stands for Tire Pressure Monitoring System. There are sensors inside your tires that monitor your tire pressure and tell you if they are low. Depending on the car, this light could mean that your tire pressure is low. If you changed your tires recently, the technician could have knocked the sensor, or if you changed rims, there may not be a sensor inside that rim and is showing up as an error code on your dash.

Most likely you have a bad tire sensor. These sensors are part of the valve stem. The dealer probably just holds the tire inflation reset button and not uses the tool. You would have to go to somebody with a scanner to read the sensor to tell you which one is faulty.

THE LIGHT CAME ON BECUASE, IF U OPEN UP THE DRIVER SIDE DOOR, ON THE SIDE SHOULD BE THE SUGGESTED AIR AMOUNT FOR THE TIRES THAT NORMAL COME WITH THE CAR. THE RIMS YOU PUT ON, I GARUNTEE ARE PROBABLY LIKE TWO TO THREE SIZES BIGGER. SO THAT SENOSR IS SENSEING SOME THING IS WRONG. CAUSING THE LIGHT TO COME ON.

Tire Pressure Monitoring Sensor. Check the air in your tires.

You should be able to get a manual from the dealer.

You can plug any tire as long as it's on the tread face, not in the sidewall. The repair person will know. It makes no difference whether you have TPMS.

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?

We took it back to the dealer. They made the necessary adjustments needed after the winter tires +rims were put on.