Oxygen (O2) Sensor Heater Control

O2 sensor operates only within a certain temperature range, approximately 545-1530°F (285-850°C). It is electrically heated to enable it to reach operating temperature quickly. When ignition is turned on, current is sent to a Positive Temperature Coefficient (PTC) resistor whose resistance increases with rising temperature. Because of this, O2 sensor quickly reaches correct operating temperature, even at low exhaust gas temperatures.