P0430: Catalyst System Efficiency Below Threshold (Bank 2)
P0430 is the passenger-side (V6/V8) equivalent of P0420. Same causes, same money-saving diagnostic path.
Severity: moderate · System: Powertrain · Safe to drive: usually, short-term. Same as P0420 — verify with O2 sensor voltage tests before replacing the converter.
Symptoms
- Check engine light
- Slight loss of power
- Higher emissions
Common causes
- Bank 2 catalytic converter failure
- Bank 2 downstream O2 sensor
- Exhaust leak
Fair repair prices
| Downstream O2 sensor (bank 2) | $180–$400 |
|---|---|
| Exhaust leak repair | $100–$500 |
| Catalytic converter (aftermarket) | $500–$1,200 |
Ranges are US market averages (parts and labor). If your shop's quote is above the high end, ask for a line-item breakdown or run it through the invoice checker.
Other codes
- P0300 — Random / Multiple Cylinder Misfire Detected
- P0301 — Cylinder 1 Misfire Detected
- P0420 — Catalyst System Efficiency Below Threshold (Bank 1)
- P0171 — System Too Lean (Bank 1)
- P0174 — System Too Lean (Bank 2)
- P0442 — Evaporative Emission Control System Leak (Small)
- P0455 — Evaporative Emission Control System Leak (Large)
- P0128 — Coolant Temperature Below Thermostat Regulating Temperature