Code Enable Criteria

DTC sets when HO2S21 oxygen content value is too far out of range from HO2S22 oxygen content value when any of the following conditions are met:

HO2S21 lambda value is 0.99-1.01 and HO2S22 voltage is more than 650 millivolts (rich) or less than 300 millivolts (lean).

Or

HO2S21 lambda is more than 1.2 (lean) and HO2S22 voltage is more than 650 millivolts (rich).

Or

HO2S21 lambda value is less than 0.8 (rich) and HO2S22 is less than 300 millivolts (lean).

All conditions must be met for more than 2-16 seconds, depending on driving state with no HO2S21 heater or HO2S22 DTCs set.