P0430Catalyst System Efficiency Below Threshold Bank 2
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- Like P0420, but for the catalyst of bank 2, so only on V and boxer engines with one catalyst per bank; Y-pipe systems with a shared catalyst report P0420 only. The module compares the oxygen sensors before and after the bank 2 catalyst – a good catalyst smooths the rear signal. GM checks on overrun and sets the code on the first trip if the ratio falls below 0.35; Ford evaluates an index ratio or fuel integration and usually needs several trips. The monitor only runs warm, in closed loop and without misfire, fuel or sensor faults.
- What you may notice
- Check engine light on, otherwise often no change in driving
- Emission test failed (higher HC, CO, NOx)
- Rattling or loss of power if the catalyst has broken up
- Likely causes
- LikelyCatalyst aged or poisoned (oil consumption, silicone, coolant)
- PossibleCatalyst overheated by misfire or rich running
- PossibleRear oxygen sensor sluggish, dirty or unsuitable
- PossibleExhaust leak ahead of or at the rear sensor
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €80 – €1,800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.