P0440 Mercedes-Benz Code - Evaporative Emission Control System Malfunction
Quick Answer
The Engine Control Module (ECM) tests the Evaporative Emission (EVAP) system for the following conditions: - Large and small leaks - Excess vacuum - Purge flow during non-commanded conditions - Fuel Level and Fuel Pressure sensor faults - EVAP Purge and Vent Valve faults The ECM monitors the Fuel Tank Pressure sensor in order to determine the level of vacuum/pressure in the EVAP system. Common causes include Missing or loose fuel cap, Incorrect fuel filler cap used, Fuel filler cap remains open or fails to close. Severity is Low - monitor the vehicle and repair when practical. The vehicle can usually be driven if no severe symptoms are present, but symptoms should be checked before extended driving.
- What it means
- P0440 Mercedes-Benz indicates Evaporative Emission Control System Malfunction.
- Common causes
- Common causes include Missing or loose fuel cap, Incorrect fuel filler cap used, Fuel filler cap remains open or fails to close.
- Severity
- Low - monitor the vehicle and repair when practical.
- Can I drive?
- The vehicle can usually be driven if no severe symptoms are present, but symptoms should be checked before extended driving.
Code P0440 Mercedes-Benz Description
- Large and small leaks
- Excess vacuum
- Purge flow during non-commanded conditions
- Fuel Level and Fuel Pressure sensor faults
- EVAP Purge and Vent Valve faults
The ECM monitors the Fuel Tank Pressure sensor in order to determine the level of vacuum/pressure in the EVAP system. The ECM commands both the EVAP Purge Solenoid and the EVAP Vent Valve ON when the conditions are met in order to apply an engine vacuum to the EVAP system. The ECM commands the EVAP Purge Solenoid OFF once the system has reached a predetermined level of vacuum. This test verifies if a vacuum can be achieved in the EVAP system. Failure to develop a vacuum may be caused by a large leak or a restriction.
What are the Possible Causes of the DTC P0440 Mercedes-Benz?
- Missing or loose fuel cap
- Incorrect fuel filler cap used
- Fuel filler cap remains open or fails to close
- Foreign matter caught in fuel filler cap
- EVAP canister or fuel tank leaks
- EVAP system hose leaking
- Fuel tank leaking
How to Fix the DTC P0440 Mercedes-Benz?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
Code Tech Notes
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0440 Mercedes-Benz code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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Frequently Asked Questions about P0440 Mercedes-Benz Code
1. What are the common symptoms of OBDII code P0440 in a Mercedes-Benz?
The common symptoms of OBDII code P0440 in a Mercedes-Benz include the check engine light being illuminated, a noticeable fuel odor, and potential issues with fuel efficiency.
2. What does the OBDII code P0440 in a Mercedes-Benz indicate?
OBDII code P0440 in a Mercedes-Benz indicates a malfunction in the Evaporative Emission Control System, specifically related to the EVAP system purge control valve circuit.
3. What are the possible causes of OBDII code P0440 in a Mercedes-Benz?
Possible causes of OBDII code P0440 in a Mercedes-Benz include a faulty EVAP system purge control valve, a loose or damaged gas cap, a leak in the EVAP system, or issues with the EVAP system hoses.
4. How can I diagnose the OBDII code P0440 in my Mercedes-Benz?
Diagnosing OBDII code P0440 in a Mercedes-Benz typically involves using an OBDII scanner to retrieve the code, inspecting the gas cap for proper sealing, checking EVAP system hoses for leaks, and testing the EVAP system purge control valve.
5. Can I continue driving my Mercedes-Benz with OBDII code P0440?
While it may be safe to drive your Mercedes-Benz with OBDII code P0440, it is recommended to address the issue promptly to prevent potential damage to the vehicle and ensure optimal performance.
6. How can I repair OBDII code P0440 in my Mercedes-Benz?
Repairing OBDII code P0440 in a Mercedes-Benz may involve tightening or replacing the gas cap, repairing or replacing damaged EVAP system hoses, testing and replacing the EVAP system purge control valve, and clearing the code with an OBDII scanner.
7. Will OBDII code P0440 cause my Mercedes-Benz to fail an emissions test?
Yes, OBDII code P0440 in a Mercedes-Benz can cause the vehicle to fail an emissions test due to the malfunction in the Evaporative Emission Control System, which is designed to reduce harmful emissions.
8. How much does it cost to repair OBDII code P0440 in a Mercedes-Benz?
The cost to repair OBDII code P0440 in a Mercedes-Benz can vary depending on the specific cause of the issue, but it may range from a simple fix like tightening the gas cap to more complex repairs involving EVAP system components.
9. Can I reset the OBDII code P0440 in my Mercedes-Benz without repairing the issue?
While you can reset the OBDII code P0440 in a Mercedes-Benz with an OBDII scanner, it is not recommended to do so without addressing the underlying problem, as the issue may persist and potentially cause further damage to the vehicle.
10. How often does OBDII code P0440 occur in Mercedes-Benz vehicles?
OBDII code P0440 related to the Evaporative Emission Control System malfunction can occur in Mercedes-Benz vehicles, especially in older models or those with high mileage, due to wear and tear on EVAP system components over time.
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