HO2S2 - Check HO2S Sensor Ground

- Key OFF.

- Disconnect the HO2S connector.

- Measure the resistance of the GND wire between the GND terminal at the HO2S sensor harness connector and ground.

- Is the resistance less than 5 ohms?

Yes -- Go to H02S3. HO2S3 - Check HO2S Wire to PCM For Open

No -- Service the HO2S GND wire.