10. O2 Sensor Ground Circuit Open

Turn the ignition off.

Disconnect the PCM harness connectors.

NOTE: Check connectors - Clean/repair as necessary.

Measure the resistance of the O2 Sensor ground circuit from the O2 Sensor harness connector to the PCM harness connector.

Fig 1: Measuring Resistance Of O2 Sensor Ground Circuit

Courtesy of DAIMLERCHRYSLER CORP.

Is the resistance less than 5.0 ohms?

Yes >>

NOTE: Determine the cause of any contamination before replacing the sensor. Inspect for the following before replacing the O2 Sensor.

Replace the Oxygen Sensor if none of the above conditions are present. See FUEL SYSTEM article.

No >> Repair the O2 Sensor Ground circuit for an open.