P0174 Nissan Sentra
System Too Lean (Bank 2) · Powertrain Code · High · Repair: Moderate
What is P0174?
The engine is running lean on bank 2. Same causes as P0171 but affecting the opposite cylinder bank on V-engines.
When the Nissan Sentra triggers code P0174 (system too lean (bank 2)), it typically points to an issue in the powertrain system. This is a high severity code, so address it promptly to avoid further damage or safety concerns. Below you'll find the most common causes, symptoms, and repair options specific to the Nissan Sentra.
This repair is rated moderate, meaning some experience and specialty tools required.
Diagnostic data on this page is compiled from publicly available repair resources and technical service bulletins. Always have a qualified mechanic confirm the diagnosis before authorizing repairs on your Nissan Sentra.
Common Causes on Nissan Sentra
- Intake manifold gasket leak on bank 2 of 3.5L VQ V6 Altima
- PCV valve failure on passenger side
- Cracked intake plenum causing vacuum leak
- Bank 2 fuel injector fouling or restriction
- Mass airflow sensor contamination
Symptoms
- Rough idle especially when cold
- Hesitation or stumble on acceleration
- Engine surging at steady throttle
- Lean misfire under load
- Poor fuel economy
- Check engine light illuminated
Notes for Nissan Sentra
P0174 is uncommon on 4-cylinder Sentra and Altima models as they only have one bank. Only V6 Altima (3.5L VQ35) will set this code.