What is a P0430 code?

P0430 means 'Catalyst System Efficiency Below Threshold (Bank 2)'. It's the sister code to P0420 and indicates the catalytic converter on the second bank of your engine (on V6/V8 engines) is failing.

Can a bad O2 sensor cause P0430?

Yes, a faulty downstream oxygen sensor on Bank 2 can send incorrect data to the car's computer and falsely trigger a P0430 code. This should be checked before replacing the catalytic converter.

P0430: Catalyst System Efficiency Below Threshold (Bank 2)

This is the companion code to P0420, specific to V6, V8, and larger engines.

P0430 Explained

The P0430 code is identical to P0420 in every way except one: it refers to **Bank 2**. If P0420 points to a problem with the catalytic converter on the side of the engine with cylinder #1, P0430 points to the converter on the opposite bank.

This code will only appear on engines with two banks of cylinders (V-engines). The causes, symptoms, and repair procedures are the same as for P0420, but all diagnostic work must be performed on the Bank 2 components.

For more details, see our guide on Bank 1 vs. Bank 2.

Related Codes

P0420 Code (Bank 1)

Learn about the identical code for Bank 1.