Oxygen Sensor: Description and Operation

Heated Oxygen Sensor (HO2S):

PURPOSE
The Heated Exhaust Gas Oxygen Sensor (HO2S) detects the presence of oxygen in the exhaust system and produces a variable voltage according to the amount of oxygen detected.

OPERATION
When operating in closed loop the Powertrain Control Module (PCM) monitors this input and correspondingly changes the duration of the fuel injection pulse width to achieve an air/fuel ratio of 14.7:1. A high concentration of oxygen (lean) in the exhaust produces a low voltage signal of less than 0.4 volt while a low concentration of oxygen (rich) produces a high voltage signal greater than 0.6 volt. The HO2S generates a voltage between 0.0 and 1.1 volts.