What the P0174 Code Means for Your 2020 Nissan Pathfinder
Your 2020 Nissan Pathfinder has triggered a P0174 diagnostic trouble code, indicating that Bank 2 of the engine is running too lean. The 2020 Pathfinder uses a 3.5-liter V6 engine (VQ35DD) producing 284 horsepower. Unlike inline engines, this V6 genuinely has two banks -- Bank 1 and Bank 2 -- so the P0174 code is telling you specifically which side of the engine has the lean condition.
Bank 2 on the Nissan VQ35 engine is typically the bank closest to the firewall (rear bank). A lean condition means the ECM is adding extra fuel to compensate for too much air in the mixture, and it has reached its correction limit.
Symptoms You Might Be Noticing
- Check engine light on the dashboard
- Rough or uneven idle, possibly with slight vibration
- Loss of power when accelerating, especially uphill or when towing
- Decreased fuel economy on your V6 Pathfinder
- Occasional hesitation or stumble during acceleration
- Engine may feel like it's running on fewer cylinders
Common Causes of P0174 on the 2020 Pathfinder V6
- Vacuum Leak on Bank 2 (35% likelihood) -- The rear bank of the VQ35DD engine has intake runner gaskets and vacuum hoses that can develop leaks. The rear location makes them harder to spot visually.
- Contaminated MAF Sensor (25% likelihood) -- The mass airflow sensor sits in the intake tract and measures incoming air. Oil mist from the PCV system or a dirty air filter can coat the sensor element.
- Bank 2 Fuel Injector Issue (25% likelihood) -- One or more injectors on the rear bank may be clogged or failing, reducing fuel delivery to those cylinders specifically.
- Exhaust Leak Near Bank 2 O2 Sensor (15% likelihood) -- An exhaust leak near the Bank 2 upstream oxygen sensor can draw in fresh air, fooling the sensor into reading lean when the actual mixture may be fine.
Diagnosis Process
- Scan for all codes -- Look for P0171 (Bank 1 lean) alongside P0174. If both banks are lean, suspect a common cause like the MAF sensor or fuel pressure.
- Check fuel trims by bank -- Compare Bank 1 and Bank 2 long-term fuel trims. If only Bank 2 is elevated, the problem is isolated to that side.
- Smoke test the intake -- Pressurize the intake manifold and look for smoke escaping on the Bank 2 side, especially around the rear intake runner gaskets.
- Inspect Bank 2 injectors -- Use a stethoscope or noid light to verify each injector on Bank 2 is firing properly.
- Check for exhaust leaks -- Inspect the exhaust manifold and pipes on the Bank 2 side for cracks or loose connections near the upstream O2 sensor.
Repair Options
- Vacuum leak repair -- Replace cracked hoses or intake manifold gaskets on Bank 2. Access to the rear bank can add labor time.
- MAF sensor service -- Clean or replace the mass airflow sensor. Cleaning is a good first step.
- Fuel injector service -- Professional cleaning or replacement of Bank 2 injectors. The VQ35 injectors are generally reliable but can clog with poor fuel.
- Exhaust repair -- Fix exhaust leaks near the Bank 2 O2 sensor. This may involve gasket replacement or manifold repair.
Estimated Repair Costs for the 2020 Pathfinder
- Vacuum leak repair: $150 - $500
- MAF sensor replacement: $180 - $400
- Fuel injector cleaning/replacement: $300 - $700
- Exhaust leak repair: $200 - $550
The Pathfinder's V6 layout means more labor time for rear-bank repairs compared to smaller vehicles. Budget accordingly.
Prevention Tips
- Replace the engine air filter every 15,000-20,000 miles
- Use quality fuel from reputable stations to protect injectors
- Inspect vacuum hoses and connections during oil changes
- Address any exhaust odors or sounds immediately
- Follow Nissan's maintenance schedule, especially for the fuel system