P0174 on the 2022 Infiniti QX60: Lean Condition Explained
The 2022 Infiniti QX60 was completely redesigned, now riding on the Nissan Pathfinder platform and powered by a 3.5L naturally aspirated V6 (VQ35DD) producing 295 horsepower, paired with a 9-speed automatic transmission. P0174 indicates that Bank 2 of the V6 is running lean — the ECM has detected excess air or insufficient fuel. On the VQ35DD, Bank 2 is the rear cylinder bank closest to the firewall.
Symptoms
- Check engine light on
- Rough or slightly unstable idle
- Hesitation during acceleration
- Marginal fuel economy decrease
- Possible occasional misfire at idle
Common Causes on the VQ35DD V6
1. Vacuum Leaks
The VQ35DD V6 in the QX60 uses a composite intake manifold with multiple vacuum ports and gaskets. The intake manifold runner control (VVEL system on the VQ35DD) adds complexity with additional gaskets and seals. Vacuum leaks from deteriorated gaskets, cracked PCV hoses, or loose vacuum connections on the rear bank are the most common cause. A smoke test is the most effective diagnostic approach.
2. MAF Sensor Contamination
The hot-wire MAF sensor in the air intake duct can become contaminated by PCV oil vapor or dust. The VQ35DD engine's dual-injection system relies on accurate MAF readings for proper fuel metering. A fouled MAF underreads airflow, causing the ECM to inject too little fuel. Cleaning with MAF-specific spray is an inexpensive first step.
3. Fuel Delivery Issues
The VQ35DD uses both port and direct fuel injection (dual injection). A weak high-pressure pump for the direct injection system, a restricted fuel injector, or a failing port injector on Bank 2 can cause lean conditions. The dual injection system provides redundancy but also doubles potential failure points.
4. Exhaust Leak Before O2 Sensor
An exhaust leak at the Bank 2 exhaust manifold gasket or the catalytic converter connection can draw in ambient air during exhaust pulses, causing the upstream O2 sensor to read falsely lean. Listen for ticking sounds at cold startup that diminish as the engine warms.
Diagnostic Steps
- Scan for all DTCs — check for P0171 alongside P0174
- Review freeze frame data for fuel trim values on both banks
- Perform an intake smoke test focusing on Bank 2 connections
- Inspect all vacuum hoses for cracks and proper connections
- Clean and test the MAF sensor
- Test fuel pressure for both port and direct injection systems
Repair Costs for the 2022 Infiniti QX60
Infiniti parts carry a premium over mainstream Nissan but are competitive with other luxury brands:
- Vacuum leak repair: $150–$400
- MAF sensor cleaning: $20–$40 (DIY)
- MAF sensor replacement: $170–$350
- Fuel pump replacement: $450–$800
- Exhaust manifold gasket: $300–$550
Driving With P0174
The naturally aspirated VQ35DD is tolerant of mild lean conditions for daily driving. You can drive normally for short trips. Avoid sustained highway driving under heavy load. The 2022 QX60 should be within Infiniti's 4-year/60,000-mile basic warranty — check your coverage.
DIY Feasibility
The QX60's engine bay provides reasonable access. MAF sensor cleaning is quick and easy. Vacuum hose inspection is a visual task. The rear bank is harder to reach but accessible with patience. For fuel system diagnostics, a Nissan/Infiniti-compatible scan tool (like Consult) provides the most detailed data.