Where is the O2 sensor located on a 1990 Camry?

On a 1990 Toyota Camry, the oxygen (O2) sensor is typically located in the exhaust system, just before the catalytic converter. Depending on the engine type, there may be one or two sensors: the upstream sensor is positioned before the catalytic converter, while a downstream sensor is located after it. You can usually find it mounted on the exhaust manifold or the exhaust pipe.