DTC P1197: 1/2 O2 Sensor Slow During Catalyst Monitor (With CALIF. Emissions): Description

1/2 Heated Oxygen Sensor (HO2S) catalyst monitor is monitored with engine running, coolant temperature more than 170°F (77°C), open throttle, vehicle speed steadily increased 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) when PCM senses 1/2 HO2S is switching from less than 0.39 volt to more than 0.6 volt fewer times than required. Possible causes for DTC to set are: excessive engine blow-by, oil or coolant consumption, defective 2/1 HO2S, defective connector or defective wiring.