How to clear P0128 Check Engine Light (CEL) (coolant temperature below thermostat regulating temperature) on a 1999, 2000, 2001, or 2002 Toyota Corolla

Parts needed:

• Temperature sensor: http://www.ebay.com/itm/271937021784
• 19mm deep socket: http://www.homedepot.com/p/Husky-3-8-in-Drive-19-mm-6-Point-Metric-Deep-Socket-H3D6PDP19MM/202913533
• 10mm socket
• Mini flathead screwdriver

Do this:

1. Park car in a place where you don't mind a little coolant leaking out, or put a basin under your car
2. Pop hood
3. Disconnect battery  (Disconnect black/negative first)
4. Remove battery from car
5. Remove engine air filter and air filter console.  You don't have to completely remove the top of the air filter console.  You can just move it off to the side. See https://www.youtube.com/watch?v=sXUNb9fTeG8 - you might need to remove two black plastic cable straps/ties which you can do by sticking in a mini flathead screwdriver in the opposite side (from the bottom).  Be careful not to drop any 10mm bolts down the hole in the air filter console.  You can wrap it in aluminum foil if you don't trust yourself.
6. Use your hands to unclip the wiring from the old temperature sensor.  It might be a tight fit, but you should be able to get your fingers in there if your fingers aren't too fat.  Be careful not to break the sensor wirings.
7. Remove the temperature sensor using the 19mm deep socket.  I used a breaker bar.
8. Some coolant might leak out, so quickly hand-screw in the new temperature sensor into the engine and tighten with the 19mm deep socket.
9. Reassemble.

The check engine will be cleared because the battery was removed, but the real test will take 50-200 miles of driving to make sure the car's computer keeps the P0128 code off.

Some people reported the temperature dial instantly going up to "H" right away, but I didn't experience that.