OBD-II diagnostic trouble code
P0430Safe to drive
Catalyst System Efficiency Below Threshold (Bank 2)
The same catalyst efficiency problem as P0420, but on bank 2's catalytic converter. On many V-configuration engines each bank has its own catalyst, so it's entirely possible for one to wear out well before the other.
Symptoms
- Often no noticeable driving symptoms — frequently a check-engine-light-only code
- Possible failed emissions/MOT/TÜV test
- A faint sulfur smell from the exhaust in some cases
Likely causes
- Aging, naturally worn-out catalytic converter on bank 2
- An upstream bank-2-specific problem (misfire, rich mixture) contaminating that catalyst
- A failing bank 2 rear oxygen sensor giving a false reading
- Exhaust leak near the bank 2 sensors
How to diagnose it
- Check for other active bank-2-specific codes (misfires, fuel trim) first
- Compare upstream vs. downstream bank 2 oxygen sensor data with a scan tool
- Inspect the bank 2 exhaust section for leaks near the catalyst and sensors
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Code names are compiled from open/standardized SAE and ISO references. Explanations, symptoms, causes and fixes are original. Covers generic (P0/C0/B0/U0) codes only — manufacturer-specific codes are planned for a future update.
Frequently asked questions
Can I drive with P0430?
In most cases, yes — P0430 is generally not an urgent safety issue and the car is usually safe to drive for a while. Still, get it checked soon, since the underlying cause can affect fuel economy or emissions the longer it's left.
How much does it cost to fix P0430?
Typical repair costs for {code} range from roughly 80 to 1800 EUR, depending on the specific cause and your car — see the fixes listed above for a breakdown.
What causes P0430?
Aging, naturally worn-out catalytic converter on bank 2 An upstream bank-2-specific problem (misfire, rich mixture) contaminating that catalyst A failing bank 2 rear oxygen sensor giving a false reading
Reviewed by Artyom SemenovAutomotive Editor · Fact-checked by Yauheni Kapliarchuk, Editor-in-Chief