P0420 on Hyundai vehicles
32 owner complaints filed with NHTSA about Hyundai vehicles mention P0420 (Catalyst System Efficiency Below Threshold Bank 1) - across 9 models. Below is where it shows up, by model and year.
Can you drive with it? Yes - the car remains driveable. Fix it before emissions testing: this code is an automatic inspection failure in most states.
Symptoms, likely causes in order and realistic repair costs are on the main P0420 page - they do not differ much by brand. This page shows what is specific to Hyundai: which models and years actually report it.
Hyundai models reporting P0420
The number next to each year is how many NHTSA complaints for that car mention P0420. Owners rarely quote trouble codes when complaining, so real occurrence is many times higher - use these numbers to compare years, not as totals.
What Hyundai owners report
“I see there was a P0420 error code related to catalytic converter oil consumption recall, but when I put in my VIN it said no recalls. This is for a 2020 Hyundai Elantra 2020. The problem comes and goes and was able to be reproduced or confirmed by a dealer Hyundai. The warning lamps, messages comes on frequently and was reportedly fixed charges $2000 for a sensor. I the code and it is all over the internet that it is a recall.but does not show up with VIN.i need assistance with getting this fixed at the dealer”2020 Hyundai Elantra · Mar 2026
P0420 on other makes
Makes with enough NHTSA reports of P0420 for their own page.
Counts are NHTSA owner complaints whose text mentions P0420 - owner-reported and unverified. Always confirm with a diagnosis of your specific vehicle.