Trouble code
P0430
Catalyst System Efficiency Below Threshold (Bank 2)
What P0430 means
Same as P0420 but on bank 2 of a V-configuration engine.
Symptoms you may notice
- Check engine light
- Failed emissions test
Common causes, cheapest first
- Failed catalytic converter
- Failing downstream oxygen sensor
- Exhaust leak
- Untreated misfire
Before you buy anythingSame warning as P0420. Confirm the sensor and the exhaust are sound before condemning the converter.
What to do next
- Confirm the code with your own scan tool, or have it read free at a chain parts store.
- Decode your VIN so you know your exact engine and build date.
- Work down the causes above from cheapest to most expensive.
- Search NHTSA for a recall or service bulletin covering this symptom on your vehicle.
- Read the engine buying guide before ordering.
P0430 is a generic OBD-II code, standardized across every make and model sold in the US from 1996 onward. The meaning is the same on any vehicle; the specific part and its location are not.
Parts
Parts commonly needed for P0430
These go to Amazon. We earn a commission if you buy, at no extra cost to you — see our affiliate disclosure. Which one you actually need depends on diagnosis — read the note above first.
Confirm fitment against your VIN on the listing page before ordering. A part that matches your year and model can still be wrong for your build date or engine code.