[g8ss]

I take it that it is bank 1, sensor 2. That means driver side downstream (after cat). Is this correct? For a 09 G8 V6

 

[GOPHERIT]

That fault code is assigned to the bank 1 sensor 2, *but* is located on the *passenger* side on V6 engine layouts. Bank 1 on the V8 engines, is located on the *drivers* side. It says that the ECM has detected a *rich fuel* condition at that location. It is then told to run 2 different tests to try to lean it out back to normal. If it fails to correct it, it sets the fault code.
They show a list of potential conditions that might cause that sensor to detect this condition, but they are a little painful to go thru. But since its one side only, and *if* its a one time fault to this point, I think you should reset it, and see if repeats. If it repeats, you can either start checking out some of those possibilities, or it recommends replacing the sensor.