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P0420 on KIA OPTIMA

Severity
Medium
NHTSA Reports
2
Most Affected
2007, 2016

What P0420 Means on Your KIA OPTIMA

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

"My check engine light keeps coming on. at first it would go off and on with no code. now it stays on with the code p0420 for the catalytic converter."

— 2007 KIA OPTIMA owner • AIR BAGS,ENGINE • Filed 01/16/2019

"I was driving the car on the high way when I suddenly heard a strange noise from the engine with a shake in the car then the car completely switched to the hybrid engine from the gas one."

— 2016 KIA OPTIMA owner • ELECTRICAL SYSTEM,ENGINE • Filed 09/21/2021

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 OPTIMA

50%
50%

Percentages based on NHTSA complaint component analysis for this vehicle.

Complaint Trend by Year

2007
1
2016
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