02 Sensor help

[fright88]

Ok so I am posting this for my fiance. Anyways she has a 01 V6 Camaro. She has had a check engine light on for a little while now. We went down to Auto zone and they pulled codes P0131 P0151 P0137
Code 131 says Input voltage from 02 sensor 1 in bank 1 is too low
151 says Input voltage from 02 Sensor 1 bank 2 is too low
137 Input voltage from 02 sensor 2 bank 1 is low

So I am guessing that sensor 1 and 2 are bad. Is this correct? How hard are these to change? Any help is apreciated. Thanks

[01rallysport]

Yeah they're probably bad. They shouldn't be hard to replace. They're located right on the exhaust manifolds before they join with the y-pipe. You'll just need a wrench to twist the old ones loose. They're probably bonded to the manifolds pretty good so it's going to take a lot of force to get them loose. And the wires just snap in to the connections. Good luck!