P0420 on Chevrolet vehicles
43 owner complaints filed with NHTSA about Chevrolet vehicles mention P0420 (Catalyst System Efficiency Below Threshold Bank 1) - across 13 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 Chevrolet: which models and years actually report it.
Chevrolet 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 Chevrolet owners report
“The welding that holds the exhaust together has failed. They offer a Special Warranty to cover only the passenger side, however it has failed and exhaust is super loud. Also reading 4 codes from check engine alert. All are P0420 (cat convertor). The smell of exhaust and cat convertor is super disgusting”2021 Chevrolet Traverse · Aug 2026
“Car uses excessive amount of oil! We have had the timing replaced and now it's stating the P0420 catalyst system efficiency below threshold bank 1.”2015 Chevrolet Equinox · 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.