P0430
Catalyst System Efficiency Below Threshold (Bank 2)
Similar to P0420, but this code indicates the catalytic converter on the engine's second bank (if your engine has two) isn't cleaning exhaust gases efficiently.
The powertrain control module (PCM) has detected that the catalytic converter system for Bank 2 is not operating at the required efficiency.
Common causes
- high
Failing Catalytic Converter
The most frequent cause, especially in high-mileage vehicles, indicating degradation of the catalyst material in Bank 2's converter.
Typical part cost: $500-2500+
- medium
Oxygen Sensor (O2 Sensor) Malfunction
A faulty O2 sensor (upstream or downstream) on Bank 2 can provide incorrect data, leading the PCM to misinterpret converter efficiency.
Typical part cost: $100-300
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First things to check
- 1Scan for other related codes, especially misfires or O2 sensor codes specific to Bank 2.
- 2Visually inspect the exhaust system on Bank 2 for any leaks, damage, or loose connections.
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Related codes
See related trouble codes
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Frequently asked questions
What's the difference between P0420 and P0430?
P0420 refers to the catalytic converter on Bank 1 of the engine, while P0430 refers to the catalytic converter on Bank 2. Bank 1 is typically the side of the engine with cylinder #1.
Will a P0430 code prevent my car from passing inspection?
Yes, in most regions that require emissions testing, a P0430 code will cause your vehicle to fail inspection because it indicates the emissions control system is not functioning correctly.
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