P0420 — Catalyst system efficiency below threshold (bank 1).

Code P0420 is a standard OBD-II diagnostic trouble code: Catalyst system efficiency below threshold (bank 1).

In ProblemsByVin's analysis of the NHTSA owner-complaint record, owners cite P0420 across 139 vehicle failure patterns. Diagnostic codes in complaints are reported by owners and are unverified — they point to where this code shows up, not a confirmed diagnosis. Open a page below for the full pattern (symptoms, mileage, repair costs owners cite).

Vehicles where owners report P0420 139 patterns · top 60

2022 Chevrolet Tahoe

powertrain — Excessive Oil Consumption and Catalytic Converter Failure

2021 Chevrolet Traverse

engine — Catalytic converter failure and rattling

2021 Kia Soul

engine — Defective piston oil rings – excessive oil consumption without warning

2020 Chevrolet Traverse

engine — Front exhaust pipe bracket cracking and weld failure

2020 Chevrolet Traverse

powertrain — Transmission Shuddering and Slipping

2020 Ford Escape

powertrain — Turbocharger failure — repeated cracking and engine damage

2020 Hyundai Tucson

engine — Excessive oil consumption (internal breakdown)

2020 Jeep Gladiator

engine — Cylinder Misfire (P0300, P0301, P0305)

2019 Ford Escape

powertrain — Transmission failure—sudden loss of drive

2019 GMC Acadia

engine — Front Exhaust Pipe Bracket Separation & Flex Pipe Damage

2019 Honda Odyssey

engine — Fuel Injector Failure

2019 Honda Odyssey

fuel system — Loss of motive power and acceleration hesitation

2019 Hyundai Tucson

engine — Excessive oil consumption (internal burning)

2019 Hyundai Tucson

powertrain — Excessive internal oil consumption

2019 Kia Soul

engine — Excessive Oil Consumption

2019 Volkswagen Atlas

engine — Engine stalling / loss of power while driving

2018 Chevrolet Traverse

engine — Exhaust System Bracket/Pipe Weld Fracture

2018 Chevrolet Camaro

powertrain — Engine stalling and loss of power during acceleration

2018 Dodge Journey

electrical — Engine Stall/No-Start Conditions

2018 Ford F-150

powertrain — Catalytic converter failure; possible misdiagnosis or premature failure

2018 Honda Odyssey

powertrain — Engine seizure and rod bearing failure

2018 Honda Fit

engine — Carbon buildup on intake valves and fuel injector failures

2018 Hyundai Elantra GT

engine — Timing chain failure / complete engine seizure

2018 Kia Soul

electrical — Engine oil consumption and sludge buildup

2017 Chrysler Pacifica

electrical — Engine Stalling / Loss of Power

2017 Dodge Grand Caravan

electrical — Engine stalling and no-start conditions

2017 Dodge Journey

steering — Steering wheel lock/seizure at highway speeds

2017 GMC Acadia

powertrain — Engine Stall / Total Power Loss While Driving

2017 Hyundai Tucson

engine — Excessive oil consumption

2017 Hyundai Sonata

engine — Engine Misfires / Loss of Power / Stalling

2017 Hyundai Santa Fe Sport

engine — Catalytic Converter Damage from Oil Sludge

2017 Jeep Renegade

engine — Excessive oil consumption leading to stalling and no-restart

2017 Jeep Renegade

powertrain — Catalytic Converter Failure (P0420 Code)

2017 Kia Forte

engine — Catastrophic Engine Failure—Rod Bearing / Connecting Rod

2017 Kia Sportage

powertrain — Loss of Power / Acceleration Hesitation / Limp Mode

2017 Kia Soul

powertrain — Catalytic converter failure / P0420 code

2017 Subaru Forester

engine — Catalytic converter failure and cabin exhaust leaks

2016 Acura MDX

engine — Emission System Failure (Catalytic Converter / Misfire Codes)

2016 Chevrolet Cruze

engine — P0420 Catalyst System Efficiency Code

2016 Chevrolet Trax

engine — Catalytic converter failure

2016 Chrysler Town and Country

powertrain — Multiple Electrical / Electronic Failures After Transmission Service

2016 Dodge Journey

engine — Engine stalling without warning

2016 Honda Pilot

engine — Connecting Rod Bearing Failure / Internal Engine Damage

2016 Hyundai Tucson

engine — Engine Seizure / Rod Bearing Failure

2016 Hyundai Veloster

powertrain — Delayed/failed gear engagement

2016 Hyundai Accent

engine — Excessive oil consumption / internal oil loss

2016 Jeep Patriot

electrical — Rough Idle and Engine Running Issues (No Clear Check Engine Code)

2016 Jeep Compass

engine — Engine stalling while driving (intermittent crank/camshaft sensor failure)

2016 Kia Optima

electrical — Hybrid system failure/loss of propulsion

2016 Kia Soul

powertrain — Catalytic Converter Clogging and Failure

2016 Kia Soul

electrical — Engine stalling and rough running

2016 Mercedes-Benz GLE-Class

engine — Catalytic converter failure (passenger side)

2015 Chevrolet Cruze

engine — Catalytic converter failure (P0420 code)

2015 Dodge Dart

engine — Catalytic converter failure

2015 Hyundai Santa Fe

engine — Catastrophic engine failure — sudden loss of power and stalling

2015 Jeep Compass

engine — Engine stall with catalytic converter-related codes

2015 Kia Forte

engine — Catalytic Converter Failure (Secondary to Engine Issues)

2015 Kia Soul

powertrain — Catalytic Converter Clogging / Plugging

2015 Kia Soul

electrical — Catalytic Converter Failure and Engine Damage

2015 Subaru WRX

engine — Rough idle and stalling

Codes are pulled from what owners wrote in their NHTSA filings — they're allegations, not a shop diagnosis. Always confirm with a live scan. Browse all diagnostic codes →