1997 Toyota Corolla 1.8L P0125 is the code Any clues?

Question

1997 Toyota Corolla 1.8L P0125 is the code. Can't find a straightforward reason for this. Any clues? 167k odometer.

Answer 1

This code is for the rear O2 sensor after the converter. This is pretty straight forward honestly. 99% of the time the sensor failed. The heater wire inside the sensor burns out so it won't go into what is called closed loop. Replace the rear O2 sensor and take it from there.

Answer 2

P0125 TOYOTA - Insufficient Coolant Temperature for Closed Loop Fuel Control
Read more: https://www.autocodes.com/p0125_toyota.html