Can someone please tell me the purpose of the Bank2 Sensor 1 oxygen sensor? AutoZone says it may be bad and at $170 I want to weigh my options. My truck seems to still run fine. Also, is there a way to clean one though the manual says don't? (ie. carb cleaner) Thanks.

Sensor 1 on either bank measures oxygen content of exhaust gases and signals rich or lean to ECM which adjusts the fuel/air mixture accordingly.

http://www.autoshop101.com/forms/h37.pdf

No, you can't clean them. Just replace them. They don't last forever. Bring your VIN to the Toyota parts department and get a part number. (you can buy it anywhere). Just make sure you get the right sensor.

Some tundra's were effected by a TSB on the oxygen sensors (mine was). This will increare the warranty period to 80k miles or so.