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:

Upstream Oxygen Sensor Location:

The upstream 025 sensor is located on the exhaust downpipe.

Downstream Oxygen Sensor Location:

The downstream O2S sensor is located near 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.