What Does P0172 Mean on Your 2022 Mercedes-Benz GLC?
A P0172 code on your 2022 Mercedes-Benz GLC (X253) indicates that the engine management system has detected a rich fuel condition on Bank 1. The 2022 GLC 300 is powered by the M264 2.0-liter turbocharged four-cylinder engine producing 255 horsepower. This single-bank engine triggers P0172 when the air-fuel mixture runs consistently richer than the target ratio.
With the 2022 model approaching mid-life, certain components are reaching the age where contamination and wear can trigger fuel system codes. Addressing P0172 now prevents more expensive repairs later.
Symptoms You Might Notice
- Check engine light illuminated
- Reduced fuel economy
- Black or dark exhaust smoke
- Gasoline smell from the exhaust
- Rough or shaky idle
- Hesitation under acceleration
Common Causes of P0172 on the 2022 GLC
- Dirty MAF Sensor - Oil vapor and road debris contaminate the hot-film air mass sensor over time, causing it to under-read airflow and trigger over-fueling.
- Crankcase Ventilation Valve Issue - The CCV valve can begin to fail at this age, allowing excess oil vapors into the intake manifold and enriching the air-fuel mixture.
- Leaking Fuel Injector - The M264's high-pressure direct injectors can develop carbon deposits or seal wear, causing them to leak fuel into the cylinder.
- Upstream Lambda Sensor Degradation - The wideband oxygen sensor can lose accuracy with age, providing the ECU with incorrect air-fuel data.
How to Diagnose the Problem
Use a Mercedes-compatible scan tool to read fault codes and fuel adaptation data. Check multiplicative fuel corrections for Bank 1. Persistent negative values indicate the ECU is actively reducing fuel output to compensate for rich running.
Inspect the air filter and clean the MAF sensor. Check the intake tract for oil contamination. Test the lambda sensor with live data. If corrections remain abnormal, perform injector testing. Consider checking for any applicable service campaigns or bulletins.
Repair Options and Cost Breakdown
- Air filter replacement - $30 to $55.
- MAF sensor cleaning or replacement - $15 to $420.
- Crankcase ventilation valve replacement - $240 to $490.
- Lambda sensor replacement - $260 to $480.
- Direct fuel injector replacement - $420 to $900.
Prevention Tips
Use premium fuel and Mercedes-approved synthetic oil. Replace the air filter on schedule. Monitor fuel economy for changes. The M264 engine benefits from periodic fuel system cleaning to combat carbon deposits. If you notice oil consumption increasing, have the crankcase ventilation system checked before it triggers a code.