Oxygen Sensor: Description and Operation

PURPOSE
The oxygen sensor measure the oxygen content in the exhaust and sends a voltage signal to the ECM.

LOCATION
The oxygen sensor is mounted in the exhaust pipe, just below the exhaust manifold.

CONSTRUCTION
The sensor consists of a steel housing, sensor tip, a 12 volt heating element and its protective sleeve. The sensor tip itself is made from a platinum covered zirconium-oxide pipe.

OPERATION
This sensor produces a measureable voltage by comparing the amount of oxygen in the exhaust gas with the amount in the ambient air.

The sensor operates only within a certain temperature range of approx. 545 - 1530°F (285 - 850°C). To allow the sensor to reach operational temperature sooner, a 12 volt signal is applied to the O2s heater. Voltage is applied in a duty cycle type signal, pulsing ON and OFF about 8 times in 10 seconds.

The exhaust gases reach the outer surface of the oxygen sensor tip via the openings in the protective sleeve. Ambient air reaches the sensor's inner surface via channels. The differance in oxygen content produces a voltage read by the ECM.