P0430 on a Mercedes-Benz: 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 Mercedes-Benz

On a Mercedes-Benz, P0430 means the rear oxygen sensor on bank 2 reports the catalytic converter isn't cleaning exhaust effectively. It appears mainly on V6 and V8 models, where each cylinder bank has its own converter and sensor pair.

Is P0430 common on Mercedes-Benzs?

P0430 is seen on higher-mileage Mercedes V6 and V8 models such as the E-Class and GLE. Oxygen sensors, exhaust leaks, and the converters themselves follow the usual wear pattern, but parts and labor cost more than on mainstream brands.

Commonly reported on: E-Class, C-Class, GLE, GLC.

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	$50–250
Test the downstream oxygen sensor and replace it if faulty	Yes	$80–250
Replace the bank 2 catalytic converter	Mechanic	$1200–3500