Catalyst Efficiency Bank 2
P0430 is the bank 2 catalyst-efficiency code. It usually appears on V6 or V8 engines with separate bank 1 and bank 2 converters.
It may not feel urgent, but emissions and underlying misfire/fuel issues should be handled before damage spreads.
Common symptoms
- Check engine light
- Failed emissions test
- Possible sulfur smell
- Possible power loss if clogged
- Often no symptoms
Likely causes
- Worn bank 2 catalytic converter
- Exhaust leak
- Oxygen sensor issue
- Misfire damage
- Fuel mixture problem
What to check before replacing parts
Scan for misfire and fuel trim codes on bank 2
Look for: An active misfire or lean/rich trim code on bank 2 means the converter is likely being damaged or overworked by that underlying problem — resolve it first.
Inspect for exhaust leaks ahead of the bank 2 converter
Look for: A leak before the converter lets in outside air that can make the downstream O2 sensor read like a failed catalyst even when the converter itself is fine.
Graph the upstream and downstream O2 sensors on bank 2
Look for: A downstream sensor that switches nearly as actively as the upstream one indicates the converter isn't storing oxygen properly and is likely worn.
Compare converter inlet and outlet temperature
Look for: Little to no temperature rise across the converter under load suggests minimal catalytic activity — supports the converter itself being the fault.
Confirm bank identification before replacing parts
Look for: Bank 2 is the cylinder bank opposite bank 1 (check the vehicle's specific layout) — ordering or installing a converter for the wrong bank wastes money and won't clear the code.
This page explains the generic P0430 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
Gear guide: Best OBD2 ScannersRead this code yourself next time — from $20 Bluetooth dongles to bidirectional scan tools.Rather have a pro handle it? Find a vetted local mechanic.