HO2S (Heated Oxygen Sensor) On-Vehicle Inspection

HO2S (Heated Oxygen Sensor) On-Vehicle Inspection

A/F (Air Fuel Ratio) Sensor, HO2S (Heated Oxygen Sensor) Removal and Installation

HO2S heater

1) Turn off ignition switch and disconnect HO2S connector.
2) Check that voltage of HO2S connector (vehicle side) between terminals "4" and "3" is battery voltage when ignition switch is in ON position.

If faulty condition is found, check power supply circuit, ground circuit and connections.





3) Using ohmmeter, measure resistance of HO2S connector (sensor side) of sensor heater between terminals "3" and "4" at sensor connector.

If faulty condition is found, replace HO2S. Service and Repair

NOTE:
Sensor temperature affects resistance value largely. Make sure that sensor heater is at specified temperature.

HO2S heater resistance
5.0 - 6.4 ohms at 20 °C (68 °F)