Q: when looking at the car with hood up where is the downstream O2 located left or right side of the car

The downstream oxygen sensor is screwed into a "bung" on the rear of the catalytic converter assembly beneath the vehicle. The sensor should be readily visible as it will have wiring connected to it. The sensor should not be removed unless it has been directly tested and the test documents a fault. Note that if you were merely given a diagnostic trouble code "referring" to the sensor such does NOT represent a direct test of the sensor. If you need direct testing of the sensor in order to determine its status and.or you want a diagnostic because the check engine light is on, please request a check engine light diagnostic. If you have further questions or concerns as you decide what to do, do not hesitate to re-contact YourMechanic because we want you to make the most of your repair dollars and help you get the best possible results.