Code 61, Degraded Oxygen (O2) Sensor

If a Code 61 is stored in memory, PCM has determined O2 sensor is contaminated or degraded because voltage change time (cross counts) is slow or sluggish.

PCM performs O2 sensor response time test when coolant temperature is more than 185°F (85°C), IAT temperature is greater than 50°F (10°C), system is in "closed-loop" or in a decel fuel cut-off mode. If Code 61 is stored, O2 sensor should be replaced. A contaminated sensor can be caused by fuel additives such as silicon, or by use of non-recommended lubricants or sealants. Silicon contamination is usually indicated by a White powdery substance on sensor fins.