Code Enable Criteria
- Engine is running.
- HO2S12 is in closed loop.
- Fuel level is more than 10 percent.
- Calculated catalytic converter temperature is less than 1724°F (940°C).
- Commanded air/fuel ratio is 14.7:1.
- Battery voltage is more than 11 volts.
- No EGR or EVAP DTCs are set.
DTC sets when HO2S12 voltage is less than 40 millivolts for more than 80 seconds.