Toyota Repair: 1996mtoyota camary V6, o2 sensors, oxygen sensor

Question
where is the oxygen sensor located? I have a check engine light on.

Answer
There are three O2 sensors, two in fornt of the catalityc converter and one in the rear, the #1 sensors, in front fail frquently so I suspect it's one of them but I don't know which one it is because I don't have the code information from the check engine light.
In any case, the bank one sensor is located in the exhaust manifold near the firewall, the bank two sensor is located in the exhaust manifold near the radiator.