Hi, I have a 2011 Dodge Journey SXT 2.7L V6 with 57000KM. I have tested the volt readings of the four O2 sensors and that the upstream sensors are showing 0.2 ~ 0.8v but one of the downstream sensors (bank 2 sensor 2) is showing similar readings but at much slower rate. Bank 1 sensor 1 is constant 0.8v. What I have a hard time figuring out is whether oxygen sensor is faulty OR is working and those readings are caused from something else (cat converter maybe?). Any other ways to determine its a cat or o2 problem would be appreciated thanks. Wouldn't want to spend thousands to replace the cat.