What P0430 Means
Same issue as P0420, but on the engine's second bank of cylinders (Bank 2) — common on V6 and V8 engines with two exhaust banks.
Common Causes
- Aging or failing catalytic converter on Bank 2
- Engine misfire on Bank 2 cylinders
- Oxygen sensor failure on Bank 2
- Exhaust leak on the Bank 2 side
Symptoms You Might Notice
- Usually no noticeable drivability symptoms
- Check engine light on
- May fail an emissions test
What to Check First
- 1
Rule out any Bank 2 misfire codes first
- 2
Check for exhaust leaks on that side
- 3
Test Bank 2 oxygen sensors
- 4
Replace the Bank 2 converter if sensors and engine performance are otherwise healthy