1996 Chevrolet Camaro O2 sensor

You should get a diagnostic fault code but it's important to understand that codes never say to replace parts and they never say a part is bad. They only indicate the circuit or system that needs further diagnosis. The sensor in question is only the cause of the code about half of the time.

Forgot to add that there are typically four oxygen sensors but it depends on the engine size and vin number. V-6 and V-8 engines have one on each side and on '96 and newer vehicles there will be one ahead of the catalytic converter on each side and another one after them.