Are Upstream and Downstream O2 Sensors Interchangeable?

A: Each vehicle is different in the amount of O2 sensors they have. ... A: The upstream sensor threads into the pipe coming from the engine, closer to the front of the car, and the downstream sensor threads into the catalytic converter, more toward the rear of the vehicle. They are not interchangeable.

Are upstream and downstream O2 sensors different?

The upstream oxygen sensor is situated before the catalytic converter whereas the downstream oxygen sensor is located after the catalytic converter. The upstream sensor monitors the level of pollutants in the engine's exhaust and sends this information to the ECU that continuously adjusts the air-fuel ratio.

Are O2 sensors interchangeable?

They are not interchangeable, one is a regular old O2 sensor and the other is what is called a "catalyst monitor" They are not the same.