P0430 Catalyst System Efficiency Below Threshold (Bank 2)
The same as P0420, but for the second catalytic converter on engines with two banks (V6, V8). Bank 2 is the side of the engine without cylinder 1.
Common causes
- Worn or failed catalytic converter on bank 2
- Faulty bank 2 oxygen sensor
- Exhaust leak
- An engine problem that damaged the converter
Symptoms
- Usually none besides the check engine light
- Failed emissions test
Can I drive with it?
Usually safe to drive in the short term – but fix any misfire first.
Tip: If P0420 and P0430 appear together, look for a shared cause such as a misfire, oil burning or a fuel problem.
Which scanner reads it?
Any OBD2 scanner reads it; live-data graphing helps compare the oxygen sensors.
Budget tools like the ANCEL AD310 read it; tools with live data and graphing – like the BlueDriver or OBDLink MX+ – help you find the cause. Not sure which fits you? Try the Find My Scanner quiz.
In the data
How common is it? At New York’s emissions inspections in 2020–21, P0430 was the #8 code found on cars that failed – 2.0% of all the codes found.
Of the vehicle complaints owners filed with NHTSA from 2015 to 2025, 81 quote P0430 – most often from Honda, Ford, Jeep owners. Complaints lean toward serious problems, so treat this as a sign of how often the code turns up in real reports, not how often cars get it.
Both sources are compared on the Trends page.
Related codes
General information to help you understand a code – not a diagnosis. Your car’s service information or a qualified mechanic has the final word. See how we research.