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P0171 on MERCEDES-BENZ C-CLASS

Severity
Medium
NHTSA Reports
2
Most Affected
2006, 2011

What P0171 Means on Your MERCEDES-BENZ C-CLASS

Real MERCEDES-BENZ C-CLASS Owner Reports (Source: NHTSA Complaints Database)

"Very strong fuel odor inside cabin of vehicle while driving. odor is very strong around drivers rear wheel and from the outside once parked. also noticed gasoline/fuel accumulation underneath vehicle around driver's side rear, on under body panels."

— 2006 MERCEDES-BENZ C-CLASS owner • FUEL/PROPULSION SYSTEM • Filed 08/27/2016

"1.What component or system failed or malfunctioned, and is it available for inspection upon request? The fuel system failure is a highly critical safety concern, and my life is at risk."

— 2011 MERCEDES-BENZ C-CLASS owner • AIR BAGS,VEHICLE SPEED CONTROL,FUEL/PROPULSION SYSTEM • Filed 10/22/2024

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 MERCEDES-BENZ C-CLASS

50%
50%

Percentages based on NHTSA complaint component analysis for this vehicle.

Complaint Trend by Year

2006
1
2011
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