DTC P0420: Notes
DTC P0420 DETECTION & CONDITION POSSIBLE CAUSES
| DTC P0420 |
Catalyst system efficiency below threshold |
| DETECTION CONDITION |
- The PCM monitors the input voltage from the rear HO2S and the front HO2S output current when the following conditions are met. If the input voltage change is extremely large compared to the output current change, the PCM determines that the catalyst system has deteriorated.
MONITORING CONDITION
- ECT: more than 70 °C {158 °F}
- Catalyst converter temperature: more than 400 °C {752 °F}
- Engine speed: less than 5,000 rpm
- LOAD: 20-50%
(maximum calculated load value varies depending on engine speed).
- Time with purge control system does not operate: more than 20 s
Diagnostic support note
- This is an intermittent monitor (Catalyst).
- The MIL illuminates if the PCM detects the above malfunction condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM.
- PENDING CODE is available if the PCM detects the above malfunction condition during the first drive cycle.
- FREEZE FRAME DATA is available.
- The DTC is stored in the PCM memory.
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| POSSIBLE CAUSE |
- Looseness of front HO2S
- Leakage exhaust gas
- Purge control system malfunction
- VSS malfunction
- ECT malfunction
- Eccentric shaft position sensor malfunction
- TWC malfunction
- PCM malfunction
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