Admin is right the easiest way to remove bank 1 sensor 2 is removing the passenger wheel. I was able to turn wheels to right and remove the front of the splash guard behind wheel with out removal and was able to reach sensor 2 from bank 1 with slotted socket mentioned above and the connector also but had to reach around the tire. This will be the 3rd time of checking to replace for code po138.Yes you can, BUT, it needs to be captured in an evacuation/recovery machine. Against Federal law to vent refrigerant into the atmosphere. Also once you open the HVAC system, you introduce air and moisture into the system. The system must be pulled into a deep vacuum to remove.
Can you not reach the o2 sensor from underneath?
*edit What if you removed the passenger wheel and plastic fender well? Its fairly easy to remove and opens up quite a bit of room. Something to consider.
**edit Another things you could do is remove the upper intake (plastic part) and you should have plenty of room.
Remove that cover . Its kind of a pain (cracked mine ),but found where the wires turn to the sensors were cracked ,probably from past handling but have repaired and spliced many wires without replacing whole harnesses. Re: temp. sensor,fuel rail sensor and the 02 sensors bank 1 sensor 2 was where the Big harness cover below the fuel pressor sensor is where I found breaks to 02 sensor and fuel rail. I don't have those codes anymore. The harness that runs in front, around the the starter was a break in my bank 2 sensor 1. Bottom line, where there's connectors with 3 or 4 wires coming out of those huge bulks of wires you'll find the breaks right where they meet leaving harnesses will be very flimsy. I learned not to replace parts til checking these probabilities.I took a look at The O2 Sensor Bank 1 Sensor 1. The O2 Sensor looks fine. The wires coming from the sensor look fine. The wires have a protective cover on them, so unless I cut the wire cover I wouldnt be able to see if the wires are frayed, etc.
Should I just replace that sensor. It is new, but like you said if its made in China it could just be a bad sensor.