Question

2008 Jeep Wrangler 3.8L Rubicon with engine code P0055

Answer 1

P0055 02 sensor heater bank 2 sensor 2 circuit heater high

Circuit high input is a way of describing there is no connection to the sensor, it is either disconnected at the harness or disconnected in the sensor itself. The location is at the left side. 

This is a catalytic monitor, Sensor listed as (1) is bank2 sensor 2