What P0174 Means on the 2024 Infiniti Q50
The 2024 Infiniti Q50 continues with the 3.0L twin-turbocharged V6 (VR30DDTT) producing 300 hp in the Luxe/Pure trim and 400 hp in the Red Sport 400. P0174 indicates Bank 2 is running lean — the ECM detected excess air or insufficient fuel. Long-term fuel trims have exceeded normal correction limits.
Symptoms
- Check engine light on
- Rough or unstable idle
- Acceleration hesitation or power loss
- Reduced boost response
- Lower fuel economy
Causes on the 2024 Q50
1. Twin-Turbo Boost Leaks
The VR30DDTT's charge air system has multiple coupler connections, intercooler joints, and clamps. Even on a new vehicle, factory assembly issues or aftermarket modifications (common on the Q50 enthusiast platform) can cause boost leaks. A pressure test at 15-20 psi through the intake identifies the source.
2. MAF Sensor Contamination
Factory residue, PCV oil vapor, or aftermarket oiled filter contamination can affect the MAF sensor. The twin-turbo engine's high airflow demands make MAF accuracy critical. Clean with approved MAF cleaner.
3. Fuel System Issue
A manufacturing defect in a high-pressure pump or direct fuel injector can cause Bank 2-specific lean conditions. The Red Sport 400's higher fuel demands make pump performance critical.
4. Intake Gasket or PCV Leak
A defective intake manifold gasket or PCV system leak introduces unmetered air. Smoke testing identifies these problems.
Diagnostic Steps
- Full DTC scan with freeze frame data
- Check fuel trim values for both banks
- Boost leak test the twin-turbo system
- Inspect all charge piping connections
- Clean and test MAF sensor
- Monitor fuel pressure under idle and boost
Repair Costs
Under Infiniti's warranty, repairs are free. Reference costs:
- Boost leak repair: $200–$500
- MAF sensor: $20–$400
- Fuel pump: $600–$1,100
- Intake gasket: $300–$550
Safe to Drive?
Lean conditions on the twin-turbo VR30DDTT are serious, especially on the Red Sport 400. Avoid hard acceleration, sport mode, and launch control. Light driving is acceptable temporarily. Contact your Infiniti dealer for warranty service.
Warranty Coverage
The 2024 Q50 has Infiniti's 4-year/60,000-mile basic warranty and 6-year/70,000-mile powertrain warranty. Manufacturing defects causing P0174 are covered at no charge. If aftermarket modifications have been installed, discuss with your dealer as they may affect warranty coverage on related components.