p0125 code

[j7a7j7a7]

I have a 1999 corolla with a p0125 code. It referes to Insufficient Coolant Temperature For Closed Loop Fuel Control. I have a obdwiz scan tool. With it the operating temperature reads 195 in just a few minutes and soon goes to 208 before the fan kicks on. I have searched online and read that this code sometimes is actually an o2 sensor. Something about toyota making a mistake when programming these cars. I just purchased this scan tool and it took awhile to learn how to get a reading from the o2 sensors but when I finally got it to work it showed sensor 2 to rapidly change voltage between 0.0 and 0.9. However sensor 1 only showed a change in voltage when I revved the engine. Is this normal or is the o2 sensor bad. Also I understand there is a temp sensor for both the gauge and the computer. Is the scanner getting its temp reading from the computers sensor and if so does this rule out that it is bad?

[j7a7j7a7]

Broke down and purchased the upstream o2 sensor. It seems to have solved the problem. Scanner shows activity on that o2 sensor and no more check engine light.