What Does P0174 Mean on Your 2022 Mercedes-Benz GLC?
A P0174 code on your 2022 Mercedes-Benz GLC (X253) indicates that the ECU has detected a lean fuel condition on Bank 2. The 2022 GLC 300 uses the M264 2.0L turbocharged four-cylinder producing 255 horsepower. A lean condition on this turbo engine warrants prompt diagnosis.
Symptoms You Might Notice
- Check engine light on
- Rough or fluctuating idle
- Reduced power and turbo response
- Decreased fuel economy
- Engine hesitation during acceleration
- Whistling or hissing from the engine area
Common Causes of P0174 on the 2022 GLC
At 20,000-50,000 miles, these are the most common causes:
- Boost Leak — Charge pipes and intercooler connections can develop leaks from thermal cycling and boost pressure.
- Vacuum Leak — Various vacuum-operated systems may have failing connections or cracked hoses.
- MAF Sensor Contamination — The mass airflow sensor can accumulate deposits that affect accuracy.
- Fuel Delivery Issue — A high-pressure fuel pump starting to weaken or an injector with carbon buildup.
How to Diagnose the Problem
- Scan with Mercedes-compatible diagnostics for all codes and adaptation data.
- Monitor fuel trim values — adaptations above +10% confirm lean running.
- Inspect charge pipes and all boost connections for leaks.
- Check vacuum hoses and connections.
- Smoke test the intake and boost system.
- Test fuel pressure under load.
Repair Options and Estimated Costs
- Boost leak repair: $200–$550.
- Vacuum hose or connection repair: $100–$350.
- MAF sensor replacement: $200–$420.
- Fuel pump or injector service: $500–$1,100.
Can You Still Drive?
Light driving for short trips is acceptable. Check your warranty — a 2022 GLC may still be within the 4-year/50,000-mile coverage. If not, find a trusted independent Mercedes shop.
Prevention Tips
- Use premium fuel exclusively.
- Follow the Mercedes-Benz service schedule without delays.
- Inspect boost connections during regular service.
- Keep the air filter clean.
- Do not defer maintenance — Mercedes repairs get more expensive when delayed.