P0171 on MERCEDES-BENZ C-CLASS — System Too Lean Bank 1

Q: "What does P0171 mean on a MERCEDES-BENZ C-CLASS?"

"P0171 indicates: System Too Lean Bank 1. This is a fuel and air metering code. 2 MERCEDES-BENZ C-CLASS owners have reported this to NHTSA."

Q: "What are the most common causes of P0171 on MERCEDES-BENZ C-CLASS?"

"Based on 2 NHTSA reports, the most commonly cited components are: Fuel/Propulsion System, Air Bags,Vehicle Speed Control,Fuel/Propulsion System. These percentages are based on the component field in owner complaints."

Q: "Is P0171 serious on my MERCEDES-BENZ C-CLASS?"

"Of 2 NHTSA reports for this code on MERCEDES-BENZ C-CLASS, none involved a crash or fire. However, any diagnostic code should be evaluated by a qualified mechanic."

Q: "What should I do if my MERCEDES-BENZ C-CLASS shows P0171?"

"1) Check for recalls on your VIN at nhtsa.gov/recalls. 2) Get a professional diagnosis — a code alone doesn't identify the exact failed part. 3) Get 2-3 repair estimates to compare."

What P0171 Means on Your MERCEDES-BENZ C-CLASS

P0171 is a diagnostic trouble code indicating: System Too Lean Bank 1. This code relates to the fuel and air metering system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.

2 MERCEDES-BENZ C-CLASS owners have reported this issue to NHTSA across model years 2006-2011. Most reports come from the 2006, 2011 model years. The most commonly reported component is Fuel/Propulsion System (50.0% of reports).

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

All reports filed by vehicle owners directly with the U.S. Department of Transportation.

📊 Complaint Trend by Model Year

1

'06

1

'11

Common Causes on MERCEDES-BENZ C-CLASS

Based on NHTSA complaint component analysis for this vehicle.

FUEL/PROPULSION SYSTEM 50%

AIR BAGS,VEHICLE SPEED CONTROL,FUEL/PROPULSION SYSTEM 50%

What To Do Next

1
Check for recalls on YOUR VIN
Go to nhtsa.gov/recalls and enter your VIN. If your vehicle is covered, repairs are free.
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
Compare repair quotes
Get 2–3 quotes. Dealer vs. independent shop prices often differ 30–50% for the same repair.

Frequently Asked Questions

What does P0171 mean on a MERCEDES-BENZ C-CLASS? ▾

P0171 indicates: System Too Lean Bank 1. This is a fuel and air metering code. 2 MERCEDES-BENZ C-CLASS owners have reported this to NHTSA.

What are the most common causes of P0171 on MERCEDES-BENZ C-CLASS? ▾

Based on 2 NHTSA reports, the most commonly cited components are: Fuel/Propulsion System, Air Bags,Vehicle Speed Control,Fuel/Propulsion System. These percentages are based on the component field in owner complaints.

Is P0171 serious on my MERCEDES-BENZ C-CLASS? ▾

Of 2 NHTSA reports for this code on MERCEDES-BENZ C-CLASS, none involved a crash or fire. However, any diagnostic code should be evaluated by a qualified mechanic.

What should I do if my MERCEDES-BENZ C-CLASS shows P0171? ▾

1) Check for recalls on your VIN at nhtsa.gov/recalls. 2) Get a professional diagnosis — a code alone doesn't identify the exact failed part. 3) Get 2-3 repair estimates to compare.