What P0174 Means on the 2024 Infiniti QX60
The 2024 Infiniti QX60 uses the 3.5L V6 (VQ35DD) producing 295 horsepower with a 9-speed automatic. P0174 indicates Bank 2 (rear cylinder bank) 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
- Slightly rough idle
- Hesitation during acceleration
- Marginal fuel economy decrease
- Possible idle instability
Causes on the 2024 QX60
1. Vacuum Leak
The VQ35DD intake manifold gaskets and vacuum connections can have factory defects. A leak on the Bank 2 side allows unmetered air into the combustion chambers. Smoke testing identifies these precisely.
2. MAF Sensor Contamination
Factory residue or early PCV contamination can affect the MAF sensor, causing underreading and lean fueling. Clean with approved MAF cleaner.
3. Dual Injection Fuel Issue
The VQ35DD uses port and direct injection. A defective injector or pump on Bank 2 can cause lean conditions from new. Fuel pressure testing confirms the issue.
4. Exhaust Leak
An exhaust gasket defect before the Bank 2 O2 sensor can cause false lean readings. Inspect for soot marks or ticking sounds at startup.
Diagnostic Steps
- Full DTC scan with freeze frame data
- Check fuel trim values for both banks
- Smoke test the intake system
- Clean and test MAF sensor
- Test fuel pressure
- Inspect exhaust connections on Bank 2
Repair Costs
Under Infiniti's warranty, repairs are free. Reference costs:
- Vacuum leak repair: $150–$400
- MAF sensor: $20–$350
- Fuel pump: $450–$800
- Exhaust gasket: $300–$550
Safe to Drive?
Light driving is safe on the naturally aspirated V6. Avoid heavy passenger loads in all three rows and have it serviced under Infiniti's 4-year/60,000-mile warranty promptly.
Warranty Coverage
The 2024 QX60 has Infiniti's 4-year/60,000-mile basic warranty and 6-year/70,000-mile powertrain warranty. All P0174-related manufacturing defects are covered at no charge. Take it to your Infiniti dealer for diagnosis and repair.