Posts Tagged: Oxygen Sensor Heater Monitor

How Does the Oxygen Sensor Heater Monitor Work?

Understanding The Oxygen Sensor Heater Monitor The Oxygen Sensor Heater Monitor’s job is to constantly monitor the operation of the oxygen sensor’s heater. There are two modes of operation on a computer-controlled vehicle: “open-loop” and “closed-loop.” The vehicle operates in open-loop when the engine is cold. During open loop, the ECM calculates fuel based on outside air temperature and engine coolant temperature sensor readings only, ignoring data from the oxygen sensors. However, once the oxygen sensors’ heaters bring the sensor up to 600°F operating temperature, the ECM switches to closed … Read More