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P0171 on SUBARU WRX

Severity
Medium
NHTSA Reports
2
Most Affected
2008, 2019

What P0171 Means on Your SUBARU WRX

Real SUBARU WRX Owner Reports (Source: NHTSA Complaints Database)

"For the last month or so i had smelled gas fumes periodically when the my car was idling. a few days ago the car went into limp mode. i had the ecu code read at a local store and the technician there stated that the engine code was "p0171 system too lean (bank 1)"."

— 2008 SUBARU WRX owner • FUEL/PROPULSION SYSTEM • Filed 02/02/2013

"At 77,000 miles, my vehicle suffered a major failure where the #2 connecting rod and piston were destroyed, requiring a short block replacement. This repair was performed by Autonation West Subaru in Golden, Colorado and was covered under the SAS gold plan, certified pre-owned 7yr/100,00mi."

— 2019 SUBARU WRX owner • ENGINE • Filed 09/07/2025

Data from NHTSA Vehicle Complaints Database. All reports are filed by vehicle owners directly with the U.S. Department of Transportation.

Common Causes of P0171 on SUBARU WRX

50%
50%

Percentages based on NHTSA complaint component analysis for this vehicle.

Complaint Trend by Year

2008
1
2019
1

What To Do Next

  1. 1
    Check for recalls on YOUR VIN

    Go to nhtsa.gov/recalls and enter your VIN. Free repairs if your vehicle is covered.

  2. 2
    Get a proper diagnosis

    A code alone doesn't tell you the exact failed part. A diagnostic at a shop ($50-$150) pinpoints the root cause before you spend money on parts.

  3. 3
    Compare repair quotes

    Get 2-3 quotes. Dealer vs independent shop prices often differ 30-50% for the same repair.

P0171 on Other Vehicles

Data sourced from the National Highway Traffic Safety Administration (U.S. Department of Transportation) and the SAE J2012 OBD-II standard. Code definitions follow the SAE J2012 / ISO 15031-6 standard. Owner reports are filed directly with NHTSA by vehicle owners. This information is provided for educational purposes only and should not replace professional automotive diagnosis. Always consult a qualified mechanic for vehicle repair decisions.

Last updated: March 2026