P0456 on MERCEDES-BENZ C-CLASS — EVAP System Leak Detected (very small leak)

Q: "What does P0456 mean on a MERCEDES-BENZ C-CLASS?"

"P0456 indicates: EVAP System Leak Detected (very small leak). This is a emission controls code. 3 MERCEDES-BENZ C-CLASS owners have reported this to NHTSA."

Q: "What are the most common causes of P0456 on MERCEDES-BENZ C-CLASS?"

"Based on 3 NHTSA reports, the most commonly cited components are: Fuel/Propulsion System. These percentages are based on the component field in owner complaints."

Q: "Is P0456 serious on my MERCEDES-BENZ C-CLASS?"

"Of 3 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 P0456?"

"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 P0456 Means on Your MERCEDES-BENZ C-CLASS

P0456 is a diagnostic trouble code indicating: EVAP System Leak Detected (very small leak). This code relates to the emission controls system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.

3 MERCEDES-BENZ C-CLASS owners have reported this issue to NHTSA across model years 2010-2011. Most reports come from the 2011, 2010 model years. The most commonly reported component is Fuel/Propulsion System (100.0% of reports).

Real MERCEDES-BENZ C-CLASS Owner Reports

Source: NHTSA Complaints Database

"My engine light jeep coming on with a p0456 code. replace gas cap and purge valve control less then year ago. however i still smell gas when i fill up tank. after it goes down to 3/4 tank i don't smell gas. when it drop below half tank the engine light comes on."

— 2011 MERCEDES-BENZ C-CLASS owner · FUEL/PROPULSION SYSTEM · Filed 06/03/2020

"When fuel tank is about 75%-100% full, the car will smell heavily of gasoline inside and around the rear of the vehicle. upon inspection, fuel pump cover/cap seems to be cracked and leaking fuel. engine code p0456."

— 2011 MERCEDES-BENZ C-CLASS owner · FUEL/PROPULSION SYSTEM · Filed 11/03/2018

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

📊 Complaint Trend by Model Year

1

'10

2

'11

Common Causes on MERCEDES-BENZ C-CLASS

Based on NHTSA complaint component analysis for this vehicle.

FUEL/PROPULSION SYSTEM 100%

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 P0456 mean on a MERCEDES-BENZ C-CLASS? ▾

P0456 indicates: EVAP System Leak Detected (very small leak). This is a emission controls code. 3 MERCEDES-BENZ C-CLASS owners have reported this to NHTSA.

What are the most common causes of P0456 on MERCEDES-BENZ C-CLASS? ▾

Based on 3 NHTSA reports, the most commonly cited components are: Fuel/Propulsion System. These percentages are based on the component field in owner complaints.

Is P0456 serious on my MERCEDES-BENZ C-CLASS? ▾

Of 3 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 P0456? ▾

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.