If amplitude of S2 is different from the model value during 100 sec under enable conditions, ECM/PCM sets DTC P0420.
Item | Detecting Condition | Possible Cause |
DTC Strategy |
•
Oxygen storage capacity (Deterioration ofCatalytic efficieny) | 1. Exhaust system 2. S2 3. Catalyst converter 4. Out of range ECT sensor 5. Exhaust manifold 6. High fuel pressure 7. Incorrect connection 8. Misfire 9. Injector 10. EGR system |
Enable Conditions |
•
Engine speed is higher than 1720rpm and lower than 2800rpm
•
Engine load is higher than 21% and lower than 63%
•
Catalyst temp.(model) is higher than 500℃
•
Closed loop control
•
There is not misfire
•
There is not malfunction on HO2S / PCSV / ECTS | |
Threshold Value |
•
Difference of ‘amplitude of downstream O2 sensor' and ‘amplitude of model signal' > 0.7 | |
Diagnostic Time |
•
100 sec. | |
MIL On Condition |
•
3 driving cycles |
※ S1 : upstream oxygen sensor / S2 : downstream oxygen sensor
