929 V6-3.0L DOHC (1993)
of oxygen in the exhaust is low (rich air/fuel ratio) and decreases when the concentration is high (lean air/fuel ratio).
Oxygen Sensor Output Voltage vs. Air/Fuel Ratio
The difference in oxygen concentration in the narrow range of optimum air/fuel ratio causes a large voltage change that is easily measured by the
PCME.
Sensor elements only react efficiently with oxygen if element temperature is around 575°F (300°C) or hotter. An electrical heating element is built
into the sensors to help warm them up to operating temperature more quickly and maintain temperature during times when sensors may cool off,
such as prolonged idle or decelerating.