DTC 61

DIAGNOSTIC AIDS
IF A Code 61 is stored in memory the ECM has determined the oxygen sensor is contaminated or degraded, because the voltage change time is slow or sluggish.

The ECM performs the oxygen sensor response time test when:

^ Coolant temperature is greater than 85 degrees C.
^ At temperature is greater than 10 degrees C.
^ In closed loop.
^ In decel fuel cut-off mode.

IF A CODE 61 IS STORED THE OXYGEN SENSOR SHOULD BE REPLACED. A CONTAMINATED OXYGEN SENSOR CAN BE CAUSED BY FUEL ADDITIVES, SUCH AS SILICONE OR BY USE OF NON-GM APPROVED LUBRICANTS OR SEALANTS, USUALLY INDICATED BY A WHITE POWDERY SUBSTANCE ON THE SENSOR FINS.