I replaced the O2 sensor and reset the check engine light. Why did the light come bac on.

Question

I cleard the light and replaced the sensor with a universal sensor and the light came back on.

Answer 1

What is the code you have recieved, There is a air flow sensor (02 sensor) which is sensor 1, and sensor 2 which is a heated 02 sensor.sensor 1 is for engine management, sensor 2 is for catalytic monitor,Being a aftermarket or a universal sensor should not be a problem provided there is no problem with  sensor signal and sensor power.If you have recieved P1164 this is a software issue. and a ECM update will be required