Truck acting up lately. Hesitation on acceleration.

Has the following code.

P0138 O2 Sensor Circuit High Voltage (Bank 1 Sensor 2)

Listed as the O2 sensor after the cat converter. I looked up the sensor on RockAuto and they show 2 sensors. Upstream and Downstream positions.

Would I be looking for the downstream sensor, seeing as how it is after the cat converter?

In the past I have had faulty O2 sensors on other vehicles, and driveabilty usually isn't affected. Hopefully it's this simple.

05 Hemi Ram with 130000km.


Thanks
codfish