Impreza L Sedan F4-22L SOHC (1997) Oxygen Sensor: Heated Oxygen Sensor
Oxygen Sensor: Description and Operation
Oxygen Sensor Heater
PURPOSE/OPERATION
The O2 sensor does not operate until a certain temperature is reached. The heater warms the sensor up faster than if it had to rely simply on
exhaust gas heat. The MPFI system then controls the A/F mixture sooner, reducing exhaust emissions.
