Q: Check engine light on on 1999 Toyota Tacoma

Rookie cbe0621eac06868b3efe0d8d1d3611e23c60d3114864ea2ec19a68cfbd3eebab
My check engine light came on and got a code PO125. They say it's the ECT sensor. Is that located at the back of the engine? Is that the cause of the check engine? It seems to run great as is.
(1) Answer
(1) Comments
The code helps to point you in a direction. This can be from a bad sensor, bad wire, poor connection, thermostat etc.
Here is some info about this fault:
My experience tells me this is a thermostat, are you seeing that the engine is not warming up to operating temperature or it takes a long time to do so? If so, replace the thermostat and reset the check engine light.
Good Luck
It seems to warm up fine. As to how long, I don't thing it takes more than normal. I can try thermostat first and see, since cost is not that great. If that doesn't work should I try the senor next? Is that sensor on the back side of the block? Thanks for helping me.