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P0420 on KIA FORTE

Severity
High
NHTSA Reports
2
Most Affected
2017, 2020

What P0420 Means on Your KIA FORTE

Real KIA FORTE Owner Reports (Source: NHTSA Complaints Database)

"Repeated engine failure. 10/1/2022 "internal problem required engine teardown found exhaust cvvt dowel pin had sheared off inside of exhaust camshaft causing excessive play. Replaced exhaust cvvt exhaust camshaft valve cover gasket rtv exhaust cvvt bolt timing chain tensioner timing chain and ocv."

— 2017 KIA FORTE owner • ENGINE • Filed 10/01/2022 ⚠️ Crash reported

"I own a 2020 Kia Forte LXS with approximately 136,000 miles. The check engine light came on with code P0420 (“catalyst system efficiency below threshold”), and an Express Oil Change & Tire Engineers location confirmed the catalytic converter is failing."

— 2020 KIA FORTE owner • ENGINE,FUEL/PROPULSION SYSTEM • Filed 08/11/2025

Data from NHTSA Vehicle Complaints Database. All reports are filed by vehicle owners directly with the U.S. Department of Transportation.

Common Causes of P0420 on KIA FORTE

50%
50%

Percentages based on NHTSA complaint component analysis for this vehicle.

Complaint Trend by Year

2017
1
2020
1

What To Do Next

  1. 1
    Check for recalls on YOUR VIN

    Go to nhtsa.gov/recalls and enter your VIN. Free repairs if your vehicle is covered.

  2. 2
    Get a proper diagnosis

    A code alone doesn't tell you the exact failed part. A diagnostic at a shop ($50-$150) pinpoints the root cause before you spend money on parts.

  3. 3
    Compare repair quotes

    Get 2-3 quotes. Dealer vs independent shop prices often differ 30-50% for the same repair.

P0420 on Other Vehicles

Data sourced from the National Highway Traffic Safety Administration (U.S. Department of Transportation) and the SAE J2012 OBD-II standard. Code definitions follow the SAE J2012 / ISO 15031-6 standard. Owner reports are filed directly with NHTSA by vehicle owners. This information is provided for educational purposes only and should not replace professional automotive diagnosis. Always consult a qualified mechanic for vehicle repair decisions.

Last updated: March 2026