P0430
Moderate severityCatalytic Converter System Efficiency Below Threshold (Bank 2)
Safe to drive short-term, but it will fail an emissions test and the cause can worsen. Get it checked within a week or two. Note: P0430 only appears on engines with two banks (V6, V8).
What does the P0430 code mean?
The P0430 code means the catalytic converter on Bank 2 isn’t cleaning the exhaust efficiently enough. It is the same problem as P0420, just on the other side of the engine.
“Bank 2” is the side that does not contain cylinder 1, so only engines with two cylinder banks (V6, V8 and similar) can set a P0430. The car measures converter performance with oxygen (O2) sensors before and after it.
Can you keep driving with a P0430 code?
Yes, short-term in most cases. The car will fail an emissions test while the code is active, and if the real cause is upstream (a misfire or fuel issue), driving on it can make things worse. Get it diagnosed within a week or two.
What causes a P0430 code?
- Worn-out catalytic converter (Bank 2)~50%
- Faulty O2 sensor on Bank 2~25%
- Exhaust leak near the Bank 2 converter~15%
- Upstream misfire or rich/lean condition~10%
How to diagnose a P0430 (check these first)
- Scan for other codes first — a Bank 2 O2 or misfire code points to the real cause.
- Confirm which side is Bank 2 on your specific engine before buying parts.
- Inspect for exhaust leaks around the Bank 2 converter and sensors.
- Test the Bank 2 O2 sensors — far cheaper than a converter.
P0430 repair cost
Typical US ranges including parts and labor (varies by vehicle):
| Oxygen (O2) sensor | $150 – $300 |
| Exhaust leak repair | $100 – $400 |
| Catalytic converter | $900 – $2,500 |
Tools & parts that help
A $20 OBD-II scanner lets you check for related codes before spending on a converter. Then you can price O2 sensors or a converter for your exact vehicle.
See top-rated OBD-II scanners ›P0430 — Frequently asked questions
Is it safe to drive with a P0430 code?
Usually yes in the short term, but the car will fail emissions and the cause can worsen. Get it checked within a week or two.
What’s the difference between P0420 and P0430?
Both mean low catalytic converter efficiency. P0420 is Bank 1 (the side with cylinder 1); P0430 is Bank 2 (the other side).
Can a bad O2 sensor cause a P0430?
Yes. A faulty Bank 2 oxygen sensor can give false readings that trigger P0430, so test the sensors before replacing the converter.
How much does it cost to fix a P0430?
From about $150 for an O2 sensor to $900-$2,500 for a catalytic converter, depending on the cause and vehicle.
Related codes
General guidance based on the standard definition of the P0430 code. A real diagnosis depends on your make, model, mileage and other symptoms. When in doubt, have a professional confirm the cause before replacing expensive parts.