Catalytic converter
P0430
Catalyst System Efficiency Below Threshold (Bank 2)
What does P0430 mean?
P0430 is the same fault as P0420 but on bank 2, the cylinder bank that does not contain cylinder 1. It only appears on V6, V8 and other engines with two cylinder banks. The engine computer has decided that bank 2 catalytic converter is no longer cleaning exhaust gases efficiently enough.
Can I keep driving with P0430?
Moderate urgency
Same practical urgency as P0420 — not an emergency, but it will fail emissions and the underlying cause can be doing ongoing damage.
Symptoms of P0430
Check engine light on, typically with normal driveability
Failed emissions or smog test
Sometimes appears alongside P0420 when both converters are aging
Common causes of P0430
A worn-out bank 2 catalytic converter
A failing bank 2 downstream oxygen sensor
An exhaust leak on the bank 2 side
A misfire or rich mixture feeding raw fuel into the converter
These are ordered roughly by how often they turn out to be the cause — but the code names a system, not a part. Confirming which one is yours takes data from the running engine.
What does it cost to fix P0430?
$200 – $2,500
Typical US independent-shop range, parts and labour included. It is wide on purpose: the cheap end is usually a sensor, a hose or a cap, and the expensive end is the major component the code was reporting on. Which one you need is a diagnosis, not a guess — and dealer rates run higher than these figures.
What does P0430 mean for your car?
This page explains what P0430 means in general. It cannot tell you which of those causes is yours, because that answer is in your car's own data. Kaiju Mechanic reads the codes your car is actually storing, plus live sensor data through any standard ELM327 adapter, and interprets it against your exact year, make, model and mileage. You can also just ask it about P0430 in chat — no adapter needed for that.
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