P0430
Catalyst System Efficiency Below Threshold Bank 2
Catalyst / emissions
Generic OBD-II
Medium
What it means
P0430 means the catalytic converter on bank 2 (the cylinder bank without cylinder #1) isn't cleaning the exhaust as well as it should. The ECM compares the upstream and downstream oxygen sensors and sees the converter falling short. The car still drives normally, but it will fail emissions and the cause should be tracked down.
Medium
Can I keep driving? Yes — the car drives normally, but it will fail emissions and the underlying cause can worsen over time, so get it diagnosed.
Common symptoms
What you'll notice
- Check-engine light on
- Failed emissions or smog test
- Slightly reduced fuel economy
- Rotten-egg (sulfur) smell in some cases
Common causes
Most likely first
- Worn-out or failed catalytic converter on bank 2Likely
- Faulty downstream (post-catalyst) oxygen sensor giving a bad readingCommon
- Exhaust leak near the sensors or a leaking manifold gasketCommon
- Upstream problem overloading the converter — a misfire or rich-running conditionLess often
- Rarely, a faulty ECM misreading sensor dataLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame and check for other codes first — fix any misfire, rich, or O2-sensor codes before condemning the converter.
- Inspect the bank 2 exhaust for leaks at the manifold, flanges, and around both O2 sensors.
- Compare upstream and downstream O2 sensor waveforms; a downstream sensor that mirrors the upstream one points to a worn converter.
- Replace the failed downstream O2 sensor if it tests bad.
- If the converter is confirmed dead and no upstream cause remains, replace the bank 2 catalytic converter.
FAQ
Quick answers
Is it safe to drive with P0430?+
Yes, short-term — the engine runs normally. But a failing converter can eventually clog and restrict exhaust, so don't leave it indefinitely, and fix any misfire first.
Can I just clear P0430?+
You can, but it returns after the emissions monitor re-runs unless the converter or its cause is actually repaired.
Related codes
Often seen with P0430
Read & clear P0430 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX