Oxygen Sensor: Testing and Inspection

To perform a complete test of the O2S sensors and their circuitry, refer to the DRB scan tool and appropriate Powertrain Diagnostics Procedures. To test the O2S sensors only, refer to the following:

Oxygen Sensor Location:

The upstream O2S sensor is located on the inlet end of the catalytic converter.

The downstream O2S sensor is located on the outlet end of the catalytic converter.

Each O2S heating element can be tested with an ohmmeter as follows:

Disconnect the O2S sensor connector. Connect the ohmmeter test leads across the white wire terminals of the sensor connector. Resistance should be between 4.5 ± 0.5 ohms and 7 ohms. Replace the sensor if the ohmmeter displays an infinity (open) reading.