P0174 on Your 2023 Nissan Murano Explained
Your 2023 Nissan Murano has set a P0174 trouble code, meaning Bank 2 of the engine is running too lean. The 2023 Murano, one of the final years for this generation, uses a 3.5-liter V6 engine (VQ35DE) making 260 horsepower with a CVT transmission. Bank 2 refers to the rear cylinder bank near the firewall on this V6 layout.
A lean condition means the air-to-fuel ratio on Bank 2 has shifted toward too much air. The ECM has been adding fuel to compensate, but the correction has exceeded its programmed limit, triggering the code.
Symptoms to Look For
- Check engine light on
- Rough or unstable idle
- Sluggish acceleration, especially with a loaded vehicle
- Reduced fuel efficiency from the normal 20/28 MPG range
- Hesitation when accelerating from a stop or merging
- Possible light misfires or engine shudder
Top Causes for the 2023 Murano
- Vacuum Leak on Bank 2 (35% likelihood) -- Even relatively new vehicles can develop vacuum leaks from loose clamps, defective gaskets, or manufacturing issues on the rear bank intake.
- MAF Sensor Contamination (30% likelihood) -- Oil vapor from the PCV system or an aftermarket air filter can contaminate the mass airflow sensor.
- Fuel Injector Issue on Bank 2 (20% likelihood) -- Partially clogged or malfunctioning injectors on the rear bank reduce fuel delivery.
- Exhaust Leak Before Bank 2 O2 Sensor (15% likelihood) -- A gasket leak or crack near the upstream O2 sensor introduces air, causing false lean readings.
Diagnostic Steps
- Pull all stored codes -- Check for companion codes like P0171, misfire codes, or MAF-related codes.
- Analyze fuel trims -- Compare Bank 1 and Bank 2 long-term fuel trims. Elevated Bank 2 confirms an isolated problem.
- Smoke test -- Pressurize the intake and look for smoke on the rear bank side.
- Test MAF sensor -- Verify readings against VQ35DE factory specs.
- Check fuel system -- Test fuel pressure and Bank 2 injector flow rates.
Repair Options
- Vacuum leak repair -- Replace hoses, clamps, or gaskets on the Bank 2 side.
- MAF sensor service -- Clean or replace the mass airflow sensor.
- Fuel injector service -- Professional cleaning or replacement of affected injectors.
- Exhaust repair -- Fix leaks near the Bank 2 O2 sensor.
Estimated Repair Costs
- Vacuum leak repair: $150 - $500
- MAF sensor replacement: $180 - $420
- Fuel injector service/replacement: $300 - $720
- Exhaust leak repair: $200 - $580
Your 2023 Murano should still be under Nissan's factory warranty. Check with your dealer before paying for any repairs.
Prevention Tips
- Use OEM or quality equivalent air filters -- avoid over-oiled aftermarket options
- Fill up with top-tier gasoline to protect the fuel system
- Report any performance changes to your dealer while under warranty
- Keep up with all scheduled maintenance per your owner's manual
- Check for any open TSBs or recalls for the 2023 model year