p0420
Moderate
Kia · SUVs
Catalyst System Efficiency Below Threshold (Bank 1)
Quick Answer
Error code P0420 on your Kia SUVs means: Catalyst System Efficiency Below Threshold (Bank 1). This is usually fixable — see the step-by-step guide below.
Affected Models
Applies to all models
KX9EV9 GT-Line 2024EV9 Light 2024EV9 Wind 2024Seltos EX 2024Seltos LX 2024Seltos S 2024Seltos SX 2024Sorento EX 2024Sorento LX 2024Sorento S 2024Sorento SX 2024Sorento SX Prestige 2024Sorento X-Line 2024Sportage EX 2024Sportage LX 2024Sportage SX Prestige 2024Sportage X-Line 2024Sportage X-Pro 2024Telluride EX 2024Telluride LX 2024Telluride S 2024Telluride SX 2024Telluride SX Prestige 2024Telluride X-Line 2024Telluride X-Pro 2024AP3AP3-EKX2MQ4MQ4-HPSKMKM-HKX
Likely Causes
How to Fix It
1
Check oxygen sensor function
2
Inspect catalytic converter for damage
3
Test exhaust system for leaks
4
Perform emissions test
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Parts You May Need
Catalytic converter
Oxygen sensor
Exhaust gasket
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