P0440 Infiniti Code - EVAP Control System Small Leak
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 Infiniti indicates EVAP Control System Small Leak.
- 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 Infiniti 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 Infiniti?
- 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 Infiniti?
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
There is an Infiniti Service Bulletin to help diagnose the P0440 code:
Infiniti Factory Service Bulletin OBDII Code P0440
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0440 Infiniti 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.
Need more information about the P0440 Infiniti code?
Need more information on how to fix the P0440 Infiniti code? Get Access to Factory Service Manuals
Need Help with the Code?
Get the P0440 Infiniti code diagnosed by a professional: Find a repair shop in your area
Frequently Asked Questions about P0440 Infiniti Code
1. What are common symptoms of an EVAP control system small leak (P0440) in an Infiniti?
- Common symptoms include the illumination of the check engine light, a noticeable fuel odor, and potential issues with vehicle emissions testing.
2. What are some possible causes of the P0440 code in an Infiniti?
- Potential causes include a loose or damaged gas cap, a faulty EVAP system purge valve, a cracked or damaged EVAP line, or a malfunctioning EVAP canister.
3. How serious is the P0440 code in an Infiniti?
- While the P0440 code is not typically an urgent issue, it should not be ignored as it can impact the vehicle's emissions and fuel efficiency. It is recommended to address the problem promptly.
4. Can I continue to drive my Infiniti with the P0440 code present?
- In most cases, it is safe to continue driving the vehicle with the P0440 code, but it is advisable to have the issue diagnosed and repaired as soon as possible to prevent potential emissions-related problems.
5. How can I diagnose the source of the EVAP control system small leak in my Infiniti?
- Diagnosing the issue may involve inspecting the gas cap for tightness, visually inspecting EVAP system components for damage, conducting a smoke test to detect leaks, and using a scan tool to monitor system operation.
6. Is it possible to repair the P0440 code in an Infiniti on my own?
- Depending on your mechanical skill level, you may be able to address simpler causes such as a loose gas cap. However, diagnosing and repairing more complex issues may require professional assistance.
7. How much does it typically cost to repair the P0440 code in an Infiniti?
- Repair costs can vary significantly depending on the cause of the code and the labor rates in your area. Simple fixes like tightening the gas cap may be inexpensive, while replacing components like the EVAP purge valve can be more costly.
8. Can the P0440 code in an Infiniti reset itself after the issue is fixed?
- In some cases, the check engine light may turn off on its own after several successful drive cycles once the underlying issue causing the P0440 code has been resolved.
9. Are there any tips to prevent the P0440 code from recurring in my Infiniti?
- To help prevent the P0440 code from reoccurring, ensure the gas cap is securely tightened after refueling, regularly inspect the EVAP system components for damage, and address any potential issues promptly.
10. How long does it typically take to repair the P0440 code in an Infiniti?
- The repair time can vary depending on the exact cause of the code and the availability of parts. Simple fixes like tightening the gas cap can be done quickly, while more complex repairs may take longer.
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