P0431

P0431

Diagnosis information - DME (DFI)

Catalytic converter, bank 2, inadequate effect

Diagnostic conditions
- Perform a short test

or:
- Engine temperature more than 60 °C (140 °F)
- Time after engine starts more than 10 seconds
- Catalytic converter temperature 500 °C ... 750 °C (932 °F ... 1,382 °F)
- 60 seconds driving with gentle acceleration at 30 ... 130 km/h (19 ... 81 mph)
- Loading of carbon canister less than 0.7
- Engine speed less than 3,000 rpm
- Lambda control ahead of catalytic converter active
- Lambda control behind catalytic converter ready for operation
- No detection of oxygen sensor, mass air flow sensor or throttle valve adjusting unit fault

Possible fault causes
- Leak in exhaust system between engine and oxygen sensor behind catalytic converter
--> this is particularly relevant when driving with a mass air flow more than 250 mg/Stroke
- Oxygen sensors ahead of and behind catalytic converter bank 2 are interchanged
- Catalytic converter bank 2 faulty