What P0174 Means for Your 2020 Nissan Murano
Your 2020 Nissan Murano has triggered a P0174 diagnostic trouble code, indicating that Bank 2 of the engine is running too lean. The 2020 Murano uses a 3.5-liter V6 engine (VQ35DE) producing 260 horsepower, paired with a CVT transmission and available all-wheel drive. Bank 2 on this V6 is the rear cylinder bank, closest to the firewall.
When the engine control module detects that its fuel corrections on Bank 2 have exceeded the programmed threshold, it sets P0174. This means there's too much air or insufficient fuel reaching the rear bank cylinders.
Symptoms You May Experience
- Check engine light illuminated
- Rough or unsteady idle
- Reduced power during acceleration, especially noticeable with passengers
- Decreased fuel economy from the Murano's typical 20/28 MPG
- Hesitation when merging or passing
- Possible engine misfires felt as a shudder
Common Causes of P0174 on the 2020 Murano
- Vacuum Leak on Bank 2 (35% likelihood) -- The VQ35DE intake system uses multiple gaskets and hoses that can deteriorate. Rear bank leaks are common and harder to spot visually.
- Contaminated MAF Sensor (25% likelihood) -- The mass airflow sensor can become fouled by oil vapor or a dirty air filter, causing inaccurate airflow readings.
- Bank 2 Fuel Injector Problem (25% likelihood) -- Carbon buildup or debris can partially clog injectors on the rear bank, reducing fuel delivery.
- Exhaust Leak Near Bank 2 O2 Sensor (15% likelihood) -- A crack or loose gasket in the exhaust near the upstream O2 sensor draws in ambient air, causing false lean readings.
How to Diagnose It
- Read all stored codes -- Check for P0171 (Bank 1 lean) and misfire codes to determine if the issue is bank-specific or system-wide.
- Monitor fuel trim data -- Long-term fuel trim on Bank 2 above +15% confirms the lean condition on that side.
- Smoke test the intake -- This is the fastest way to find vacuum leaks. Focus on the rear bank intake connections and gaskets.
- Test the MAF sensor -- Compare live readings to known-good specs for the VQ35DE engine.
- Check fuel pressure and injector balance -- Verify the fuel pump delivers adequate pressure and Bank 2 injectors flow correctly.
Repair Options
- Fix vacuum leaks -- Replace deteriorated hoses, clamps, or intake manifold gaskets on the rear bank.
- Clean or replace MAF sensor -- Try MAF cleaner first. Replace if readings remain out of spec after cleaning.
- Service fuel injectors -- Professional ultrasonic cleaning or new injectors for Bank 2.
- Repair exhaust leaks -- Replace gaskets or repair cracks near the Bank 2 O2 sensor location.
Estimated Repair Costs for the 2020 Murano
- Vacuum leak repair: $150 - $500
- MAF sensor replacement: $170 - $400
- Fuel injector service/replacement: $280 - $700
- Exhaust leak repair: $200 - $550
The Murano is a mid-size luxury crossover, so parts pricing falls between economy cars and full-size SUVs.
Prevention Tips
- Replace the engine air filter every 15,000-20,000 miles
- Use quality fuel from top-tier gas stations
- Have vacuum hoses inspected during oil changes
- Address check engine lights promptly before secondary damage occurs
- Follow Nissan's recommended maintenance schedule for your Murano