P0421
P0421Catalytic conversion, bank 1 - above limit value
Diagnostic conditions
- Battery positive voltage between 10 V and 16 V
- Temperature when engine starts > -15 °C
- Time after engine starts > 10 seconds
- Catalytic converter temperature between 500 °C and 800 °C
- 50 seconds of driving with a load range between 20 % and 50 %
- Loading of activated carbon filter < 8
- Engine speed between 1,360 rpm and 2,600 rpm
- Oxygen sensing in front of catalytic converter active
- Oxygen sensing behind catalytic converter ready for operation
- No other mixture faults stored
Possible cause of fault
- Oxygen sensors in front of and behind catalytic converter are interchanged
- Catalytic converter faulty
Affected pins
-
Diagnosis/troubleshooting
NOTE:
- The diagnosis function compares the actual amplitudes of the rear oxygen sensor with the amplitudes of a computed model. These amplitudes allow conclusions to be drawn about the ability of the catalytic converter to store oxygen.
- The diagnostic conditions can also be 'enforced' by the "catalytic converter" short test using the 9588 Porsche System Tester II
Distinguishing feature of both sensors:
Oxygen sensor in front of catalytic converter (LSU) has a six pin plug
Oxygen sensor behind catalytic converter (LSF) has a four pin plug
