What Does P0174 Mean on Your 2024 Mercedes-Benz GLC?
A P0174 code on your 2024 Mercedes-Benz GLC (X254) means the engine control unit has detected a lean fuel condition on Bank 2. The 2024 GLC 300 uses the M254 2.0L turbocharged four-cylinder with 48-volt mild hybrid technology, producing 258 horsepower. A lean condition on this engine needs prompt professional attention.
Symptoms You Might Notice
- Check engine light on
- Rough or unsteady idle
- Reduced power and boost
- Lower fuel economy
- Hesitation during acceleration
- Hissing or whistling from the engine bay
Common Causes of P0174 on the 2024 GLC
The M254 engine in the GLC uses advanced turbocharging and direct injection:
- Boost Leak — Charge pipes, intercooler connections, or the turbo inlet seal can leak pressurized air, causing a lean condition under boost.
- Intake System Leak — Intake manifold gaskets or vacuum hoses can develop leaks.
- Fuel Injector Problem — A clogged or underperforming direct injector limits fuel delivery.
- MAF Sensor Issue — Contamination or a defect in the mass airflow sensor causes metering errors.
How to Diagnose the Problem
- Scan with Mercedes-compatible diagnostic tool for all codes and freeze frame data.
- Monitor fuel trim adaptations. Values above +10% confirm the lean condition.
- Inspect charge pipes, intercooler connections, and turbo inlet for leaks.
- Check all vacuum hoses and intake gaskets.
- Smoke test the boost and intake system.
- Test fuel pressure under load.
Repair Options and Estimated Costs
- Boost leak repair: $250–$600.
- Intake manifold gasket: $300–$700.
- Fuel injector replacement: $550–$1,200.
- MAF sensor replacement: $200–$480.
Can You Still Drive?
Drive gently for short distances. Your 2024 GLC is under Mercedes-Benz's warranty. Schedule a dealer appointment to have the lean condition diagnosed and repaired at no cost.
Prevention Tips
- Use your Mercedes-Benz warranty for all engine concerns.
- Always use premium fuel (91+ octane).
- Follow the recommended maintenance schedule.
- Keep the air filter clean.
- Address all dashboard warnings immediately.