Understanding the P0430 Code on Your 2022 Mercedes-Benz C-Class
The P0430 code on your 2022 Mercedes-Benz C-Class means the bank 2 catalytic converter isn't cleaning exhaust gases as well as it should. The 2022 C 300 comes with a 2.0L turbocharged four-cylinder M264 engine producing 255 horsepower. This engine uses a twin-scroll turbocharger and relies on catalytic converters to reduce emissions before they exit the tailpipe.
Your Mercedes-Benz's ECU tracks converter performance through oxygen sensors positioned before and after the converter. When the downstream sensor on bank 2 starts producing voltage swings similar to the upstream sensor, it indicates the converter's catalyst material has degraded, triggering the P0430 code.
Symptoms You Might Notice
- Check engine light illuminated
- Reduced fuel economy
- Sulfur or rotten egg smell from exhaust
- Subtle loss of engine power
- Emissions test failure
Common Causes of P0430 on the 2022 Mercedes-Benz C-Class
- Catalytic converter degradation — The M264 engine's turbocharger produces high exhaust temperatures that can accelerate catalyst material breakdown over time.
- Faulty downstream O2 sensor — Oxygen sensors wear out and can provide inaccurate readings, triggering the code even when the converter is fine.
- Exhaust leak — A leak at a gasket, flange, or weld seam near the converter introduces false air into the system.
- Engine performance issue — Misfires, rich running conditions, or oil burning can damage the converter internally.
How to Diagnose the Problem
Use a Mercedes-compatible scanner like the XENTRY system or a quality aftermarket tool to pull all codes and freeze frame data. Check for related codes pointing to O2 sensor issues or misfires. Use live data to monitor the bank 2 oxygen sensor signals. The downstream sensor should show a relatively stable voltage compared to the fluctuating upstream sensor.
Visually inspect the exhaust from manifold to tailpipe. Look for soot deposits that indicate leaks, and check all gasket joints. Tap the converter gently to check for internal rattling.
Repair Options and Costs
- Catalytic converter replacement: $2,300 – $4,000 parts and labor. Mercedes OEM converters are expensive.
- O2 sensor replacement: $280 – $520 including labor.
- Exhaust leak repair: $150 – $400 depending on severity.
- Engine repair for underlying issues: $250 – $900 for spark plugs, coils, or injectors.
Can You DIY This Repair?
O2 sensor replacement is a moderate DIY project if you have the right tools and can access the sensor. Catalytic converter replacement on a Mercedes-Benz is complex and best left to professionals. Check your warranty status first — the 2022 C-Class should still be under the federal emissions warranty.
Prevention Tips
- Use premium fuel as Mercedes-Benz specifies
- Address any engine codes or misfires immediately
- Follow the scheduled maintenance plan for your C-Class
- Avoid frequent short trips that prevent the converter from reaching proper temperature
- Use Mercedes-Benz approved engine oil