Diagnostic Aids

PCM will not go into "closed loop" if this DTC has failed during the current ignition cycle. Use scan tool to review malfunction history diagnostic information. This data can be used to duplicate a problem. Check tightness of terminal connections. Normal scan tool readings in "closed loop" will show the O2S voltage varying between 10-999 mV. DTC can also set or cause false O2S reading of O2S ground becomes loose or corroded.