The oxygen sensor reacts with the oxygen in the exhaust gases and sends a voltage signal to the ECU based on this reaction. A low voltage signal indicates too much oxygen or a lean condition while a high voltage signal indicates not enough oxygen or a rich condition. The ECU uses this information along with other sensor inputs to calculate air/fuel ratio.
| Fig. 1: The O2sensor (A) is threaded into the exhaust
so that the element (B) is in the exhaust gas stream
|
The oxygen sensor is threaded into the exhaust manifold and/or pipes on all engines except turbocharged engines. On turbocharged engines, the sensor is screwed into the turbocharger itself.
Some Mazda engines utilize more than one oxygen sensor, often having a front and rear sensor (as in V6 engines) and/or pre- and post catalytic converter sensors (which enables the ECU to measure catalytic converter efficiency).
