P0440 Nissan 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 Nissan 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 Nissan 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 Nissan?
- 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 Nissan?
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 a Nissan Service Bulletin to help diagnose the P0440 code:
Nissan Factory Service Bulletin OBDII Code P0440
User Submitted Video
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0440 Nissan 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 Nissan Code
No Frequently Asked Questions about P0440 Nissan Code found.
Discuss the causes and fixes for P0440 Nissan OBDII Code
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i have this code on a 1999 nissan altima gxe. p0440. where should i start. i did the gas cap thing by un srewing it and replacing it. but iam also getting codes p0325,p0440,p1490,p1448. and dont know where to start.. thanks
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You could start by erasing all the codes and work with the one that comes back first. You should also check the canister and make sure is not damage.
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I replaced gas cap it also had tune up v.alve cover gasket was fixed. check engine light is on. running out of money to keep getting it worked on. also have to fix ac and blower motor again. om sick and have to have ac.
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Unfortunately there are many things that could cause that code. The gas cap is the fisrt thing, but you already did that. If the code came up after the valve cover repair, then there is a chance that whomever did the valve covers left a loose hose or component.
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I have a P0440 code evap leak and a P0325 knock sensor code should i replace the purge tank and see what happens?
1997 nissan pathfinder -
i have no idea where the knock sensor is either, what other than a fauly gas cap can cause evap leak could this have to do ith muffler or feul filter , ? Thanks
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The muffler (exhaust system) or fuel fuel will not cause the P0440 code.
The knock sensor is under the intake plenum. Check the information: ( http://x.nissanhelp.com/for... ). You may be able to relocate the knock sensor.
Now, diagnosing the P0440 code is not easy. most of the times the problem is the gas cap, but if the gas cap is OK, you have a damage EVAP system hose or a leaking component. One common EVAP system component that leaks is the "EVAP Canister Purge Volumen Control Valve"
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bought my nissan maxima from a car auction and have had nothing but problems with y car i hate my car
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I don't know if anyone is still responding to this, but I have a 1996 Nissan Maxima. I replaced the Canister Purge valve, Canister Vent valve, pretty much every Evap valve, the hoses to those valves, evap/purge valve sensors, fuel tank pressure sensor, manifold air pressure sensor, and P0440 is the code that always pops up....... Damn you, P0440. The war continues...
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Did you check or replaced the canister? Sometimes water gets into the canister, and also, due to the mileage of your Maxima it's possible that the canister is already damage.
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Yes tha canister. Sounds like you may have a very small leak. Small leaks are not easy to find. The next step is to use an smog machine. You have to fill the entire EVAP system with smog and check where the is the leak.
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