How many oxygen sensors are on a Mazda 3?

The number of oxygen sensors on a Mazda 3 can vary depending on the model year and engine type. Generally, most Mazda 3 models are equipped with two oxygen sensors: one upstream (pre-catalytic converter) and one downstream (post-catalytic converter). Some models with more complex engine configurations may have additional sensors. Always refer to the specific service manual for the precise configuration of a particular vehicle.