What Does P0420 Mean on a 2022 Kia Sorento?
The P0420 code on your 2022 Kia Sorento indicates the ECM has found that the Bank 1 catalytic converter is operating below its efficiency threshold. The 2022 Sorento features the 2.5L Smartstream MPI engine (191 hp) with an 8-speed automatic in base trims, the 2.5L Turbo GDI (281 hp) with an 8-speed DCT in higher trims, and hybrid options with a 1.6T powertrain. The gasoline engines use integrated exhaust manifold/converter assemblies.
Your 2022 Sorento is covered by the federal emissions warranty. A Kia dealer visit is the recommended first step.
Symptoms You Might Notice
- Steady check engine light
- Mild fuel economy decrease
- Faint sulfur smell from exhaust
- Slight power hesitation
- Emissions test failure
Common Causes on the 2022 Sorento
1. Catalytic Converter Degradation
The 2022 Sorento's engines, particularly the 2.5T, produce substantial exhaust heat. The turbocharged converter handles higher temperatures than the naturally aspirated version. After a few years of driving, thermal cycling begins degrading the catalyst, especially with city commuting and towing.
2. Downstream O2 Sensor Issue
The post-converter sensor can degrade from heat and contamination. On a newer Sorento, sensor testing should be the first diagnostic step. It is the cheapest potential fix.
3. Software Calibration
Kia may have released ECM updates that adjust emissions monitoring parameters. A reflash at the dealer could resolve the code.
4. Exhaust Leak
The converter-to-pipe connection and turbo downpipe gasket (on the 2.5T) can develop leaks from thermal cycling. Small leaks introduce false air readings.
How to Diagnose the Problem
- Kia dealer diagnosis — Check emissions warranty eligibility.
- TSB check — The dealer searches for applicable bulletins.
- O2 sensor data — Live data comparison identifies the root cause.
- Exhaust inspection — All connections checked for leaks.
- Converter efficiency test — Temperature testing verifies converter operation.
Repair Options
Professional Repair (Recommended)
The federal emissions warranty covers the converter for 8 years/80,000 miles. Your 2022 Sorento should qualify for covered repair. The 2.5T's turbo-integrated exhaust requires dealer-level expertise.
DIY Repair
O2 sensor replacement is feasible for DIYers. Converter work is more complex, especially on the turbo model. For warranty-covered vehicles, use the dealer.
Estimated Repair Costs
- Catalytic converter assembly: $500 - $1,400
- Downstream O2 sensor: $100 - $250
- ECM software update: $0 - $150
- Exhaust leak repair: $100 - $350
Prevention Tips
- Use the recommended fuel grade for your engine
- Follow the maintenance schedule, especially oil changes for the turbo
- Address engine performance issues promptly
- If towing, allow cool-down periods before shutdown
- Keep the air filter clean