P0420 on Hyundai Vehicles
The bank 1 catalytic converter no longer stores enough oxygen to clean the exhaust properly. P0420 →
30Complaints mentioning the code
#4Rank among 14 brands
4.2%Share of Hyundai DTC complaints
In NHTSA owner complaints we analyzed for Hyundai, P0420 was mentioned 30 times.
Most mentioned models
| Hyundai Tucson | 7 | |
|---|---|---|
| Hyundai Santa Fe Sport | 5 | |
| Hyundai Sonata | 4 | |
| Hyundai Veloster | 4 | |
| Hyundai Elantra | 2 | |
| Hyundai Santa Fe | 2 |
Model years mentioned
Components named in these complaints
- Engine (24)
- Unknown Or Other (6)
- Power Train (6)
- Fuel/propulsion System (4)
- Electrical System (2)
Reports with a crash: 0 · fire: 1 · injuries: 0
Often appears together with
P0014
Powertrain
The bank 1 exhaust cam won't follow its target and stays too far advanced; think oil, valve…
Moderate
P0302
Powertrain
Cylinder 2 keeps misfiring. On inline engines it's a middle cylinder, so rule out coolant…
Moderate
P0441
Powertrain
The ECU opened the purge valve but saw the wrong flow: too little, too much, or at the wrong…
Low
Possible causes
- Catalytic converter worn out or poisoned by age, oil ash, coolant or silicone
- Rear (downstream) O2 sensor slow, contaminated or reading out of range
- Exhaust leak ahead of the rear O2 sensor (manifold, gasket, flex pipe)
- Engine fault that overheated the converter: misfire, rich mixture, leaking injector
Related codes
Source: NHTSA Complaints API (US government open data), analyzed by DTC mention.