P0174 Toyota Tacoma
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 Toyota Tacoma 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 Toyota Tacoma.
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 Toyota Tacoma.
Common Causes on Toyota Tacoma
- Air induction system leak on bank 2 of 3.5L or 4.0L V6
- Cracked intake manifold gasket on passenger side
- Bank 2 fuel injector failure on 5.7L V8 Tundra
- Secondary air injection system malfunction on bank 2
- Mass airflow sensor contamination from dusty conditions
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 Toyota Tacoma
Tacoma 4-cylinder models will not set P0174. On 4Runner and Tundra V6/V8 engines, check secondary air injection system which can trigger lean codes.