P0430 on a Subaru: Causes, Fixes & Repair Cost

🟠 Moderate severity · drivable

Drivable in the short term, but the bank 2 converter problem should be checked soon.

What P0430 means on a Subaru

On a Subaru, P0430 tells you the bank 2 catalytic converter isn't cleaning exhaust as well as the computer expects. Four-cylinder Boxer engines have only one bank, so this code mainly shows up on six-cylinder models like the Outback 3.6R.

Is P0430 common on Subarus?

P0430 is less common on Subaru than P0420 because most Subarus sold are four-cylinder models with a single bank. When it does appear, it's typically on higher-mileage six-cylinder Outbacks and Legacy models with a worn converter or oxygen sensor.

Commonly reported on: Outback, Legacy, Tribeca.

Symptoms

Check engine light is on
Reduced fuel economy
Possible rotten-egg smell from the exhaust
Often no noticeable driving symptoms early on

Common causes

most common: Worn or failing catalytic converter on bank 2
common: Faulty downstream oxygen sensor on bank 2
common: Exhaust leak before or near the downstream sensor
less common: Unfixed misfire or rich fuel mixture that damaged the converter

How to fix it

Fix	DIY?	Typical cost
Inspect for exhaust leaks and repair them before replacing anything	Yes	$50–200
Test the downstream oxygen sensor and replace it if faulty	Yes	$60–200
Replace the bank 2 catalytic converter	Mechanic	$700–2600