Emission control
P0430 — Catalyst System Efficiency Below Threshold (Bank 2)
The ECU compares the oxygen sensors before and after the catalytic converter on bank 2 and finds that the converter is not working as efficiently as it should.
Common causes
- Worn or failed catalytic converter on bank 2
- Faulty downstream oxygen sensor on bank 2
- Exhaust leak before or around the sensors
- Misfire or fuel mixture problems on bank 2
- Oil or coolant contamination of the converter
Symptoms
- Check engine light, often the only symptom
- Failed emissions test
- Reduced power if the converter is clogged
- Rotten-egg smell in some cases
How to check
- Repair any misfire and fuel trim codes first
- Check for exhaust leaks around the bank 2 sensors
- Compare upstream and downstream oxygen sensor signals on bank 2
- Check backpressure; replace the converter only if sensors and mixture are good
Can you keep driving?
Usually drivable, but find the root cause to avoid clogging the converter. Never ignore an active misfire.
Related codes
Frequently asked questions
- What does P0430 mean?
- The catalytic converter on bank 2 is not cleaning the exhaust as well as expected.
- What is the difference between P0420 and P0430?
- P0420 refers to bank 1, P0430 to bank 2.
General reference information. It does not replace a diagnosis on your own vehicle. The same code can have different causes depending on make, model year and engine; check the manufacturer's documentation or ask a technician with a scan tool.