10. O2 Sensor Ground Circuit

With the ignition on.

Measure the voltage on the O2 Sensor Ground circuit in the O2 Sensor harness connector.

Fig 1: Measuring Voltage On O2 Sensor Ground Circuit In O2 Sensor Harness Connector

Courtesy of DAIMLERCHRYSLER CORP.

Is the voltage below 0.1 volt? 

1. Yes  >> Check the fuel system for contaminates. Also, check the exhaust system for any leaks. See EXHAUST SYSTEM article.

   See POWERTRAIN VERIFICATION TEST - VER 2  .

2. No  >> Check the O2 Ground circuit for a short to ground, open, or short to voltage. Inspect the O2 Sensor connector and the PCM harness connector. If OK, replace and program the Powertrain Control Module. See ELECTRONIC CONTROL MODULES article.

   See POWERTRAIN VERIFICATION TEST - VER 2  .