When Monitored

This diagnostic runs when the following conditions are met:

• No other O2 Sensor circuit faults active.
• There are several different catalyst efficiency monitoring windows. Each specific window has several different enable conditions. The best opportunity for the catalyst efficiency monitor to run is:
  • Engine temperature above 70°C (158°F).
  • Engine speed between approximately 1000 RPM and 3000 RPM.
  • Vehicle speed between 20 mph and 85 mph, under moderate engine load.