Monitored & Set Conditions

1/1 Heated Oxygen Sensor (HO2S) catalyst monitor is monitored when engine is running, coolant temperature is more than 158°F (70°C), open throttle, vehicle speed steadily increases to more than 18 MPH but less than 55 MPH, and light engine load exists for at least 5 minutes. DTC will set in Powertrain Control Module (PCM) memory when PCM senses 1/1 HO2S is switching from less than .39 volt to more than .6 volt fewer times than required. Possible causes for DTC to set are: intermittent condition, exhaust leak, defective 1/1 HO2S, or defective connector or wiring.