Drive with caution — fix soon.
P0430 means the computer judged the catalytic converter on Bank 2 (the cylinder bank opposite Bank 1) to be working below its required efficiency. As with P0420, the real culprit can be an oxygen sensor, an exhaust leak, or another engine issue rather than the converter itself. This code only appears on engines with two cylinder banks, like many V6 and V8 vehicles.
$200 – $2200
Varies by vehicle and root cause.
Yes, it's generally safe for short-term driving and the car behaves normally. You'll fail emissions, so have it diagnosed within a few weeks to avoid a bigger repair.
Repairing an oxygen sensor or exhaust leak typically costs $200-$500, while a catalytic converter replacement on Bank 2 often runs $900-$2,200 depending on the vehicle.
It's moderate. The car stays drivable, but the emissions system isn't performing and ignoring a root cause like a misfire can damage the converter.
They're the same fault on different cylinder banks. P0420 is Bank 1 and P0430 is Bank 2, the side of the engine opposite cylinder number one.