My sons cars check engine light came on and he had it checked at auto zone. they said its the O2 sensor, bank 2 sensor 2. Where is that one located at and is it hard to replace?
Its the sensor after the cat on the drivers side of the vehicle.
It measures cat converter efficiency & will throw a code if the cat or the sensor is faulty. Quite easy to replace on a difficulty rating I'd say 2 out of 5. They can sieze in the hole though & so a liberal dosage of wd40 or penetrating oil can be used followed by a good 7/8'' or 22mm box wrench if it will fit over the electrical connector, if not cut the wire.
FWIIW, the odds do not favor the O2 sensor being bad. More likely a bad cat. There is a saying that cats do not die. They are murdered. Meaning that cats will usually last the lifetime of the car. But when they fail, it is usually something external to the cat causing the cat to go bad.
Depending upon the MY, suspect a bad head gasket allowing oil or anti-freeze to contaminate the exhaust.
You might get lucky and the O2 sensor is bad. And then again, maybe the all the "nasty" video girls really are just 18 and it really is their "first time".