The check engine light is on and this is the code that is stored. Does this mean the O2 sensor closest to the engine is at fault and needs replacing?

thanks for your help!!!

The check engine light is on and this is the code that is stored. Does this mean the O2 sensor closest to the engine is at fault and needs replacing?

thanks for your help!!!

Bank one Sensor one.
Is first sensor on bank one or left side of engine.
What engine and year and the code no?
Any other codes?
A code does not say replace sensor it says check it out.
MT