Check engine light on. Code P0440.

code p0440 refers to evaporative emission (EVAP)system malfunction===causes--hose connections--intake leak--EVAP canister purge valve. Check all hose connections and replace the canister purge valve.. If you can locate the unit you should be able to replace it yourself

find top of coolant fill find hose closest to it follow hose over to engine there under cast metal connection to engine there is thermostat

To kinda give you an idea where to start, go to this page http://repairpal.com/OBD-II-Code-P0440 let me know what you think after reading this...

I assume you mean the engine is over heating. Would check the thermostat first by removing it and see if it still over heats.If not, replace the thermostate, if it does then the radiator might be plugged up and would need to be fixed or replaced.

Diagnostib Test Code (DTC) P0440 is defined by SAE J2012 simply as "Evaporative Emission System".

This code is what I call a "catch-all" code for the evap system. This is the code that sets when all the other EVAP codes do not apply and there is a malfunction detected in the EVAP system.

It is not really hard to diagnose this code if you have the correct equipment and understand how the EVAP system operates.

How DTC P0440 sets:

The system is tested when there are no electrical problems with the Purge Control Solenoid Valve (PCSV) or Canister Vent Solenoid Valve (CVSV) circuits and the Fuel Tank Pressure (FTP) sensor voltage is within the operating parameters. The Powertrain Control Module (PCM) commands the CVSV to close and the PCSV to open and apply vacuum. It then looks for a change in the FTP voltage to indicate that there is a vacuum being drawn on the fuel tank. If there is no change, DTC P0440 sets.
If there is a change in FTP voltage, the PCM draws the vacuum to a predetermined set point and closes the PCSV (leaving the CVSV also closed) and looks for decay in the vacuum in the tank as evidenced by the FTP voltage. If the predetermined set point cannot be reached, DTC P0440 sets. If the set point is reached and the decay is faster than allowed over a predetermined time period, DTC P0440 sets.

It should also be noted that the monitor for this code is a "type B" DTC, meaning that it must fail on two successive drive cycles before it will turn the check engine light on. So, if it fails on the current drive cycle, then the conditions for running the monitor are not met on the next drive cycle, the code will not set on the second or third drive cycles. All conditions must be met and the monitor must fail two drive cycles in a row. This explains why it may take a week or two before the check engine light comes back on.

This code is very easy to diagnose using a scan tool that is capable of performing "purge and seal" tests and graphing the FTP voltage over time. The technician can actually "see" the vacuum being drawn on the fuel tank and the vacuum decay by doing it this way. Repairs can be verified this way without having to drive the vehicle several times to get the EVAP monitor to run.

By running the evap purge/seal function on the scan tool and using hose clamping pliers, different parts of the system can be checked by clamping off the hoses that connect the components and watching the FTP voltage graph. If there is no change in the FTP voltage when the system is commanded to purge, a vaccum gauge should be used to verify that the purge solenoid is actually working and that vacuum is being applied to the rear of the vehicle There could be leaks in the line between the purge solenoid and the canister.

For an example of how this works:

Possible rust holes in the filler neck and/or a defective fuel cap can be determined if there is no change in the FTP sensor voltage or rapid decay upon the initial test that goes away when the filler tube hose is clamped off between the filler tube and the fuel tank. A sticking CVSV can be determined in the same fashion by clamping off the hose between the charcoal canister and the CVSV.

Holes in the hoses themselves can also be diagnosed the same way by disconnecting them from the vacuum source end and plugging the source tube. Example, remove the vent hose from the canister and plug the hole in the canister. If the problem goes away, it is either the hose leaking or the CVSV leaking. So, reconnecting the hose to the canister and disconnecting it from the CVSV and plugging the end of the hose will tell you if it is the hose or a sticking CVSV.

This may sound really involved, but it is very easy to diagnose this way once you know how.

There has been a service bulletin isued for that code. I have run into this before, also the wires comming out of the connector. That would bethe first thing to check. Here is what the bulletin states. Emissions - SES Lamp ON/DTC P0440 (EVAP) SetNotesFile In Section: 06 - Engine/Propulsion SystemBulletin No.: 02-06-04-044Date: August, 2002TECHNICALSubject: Service Engine Soon (SES) Light Illuminated, DTC P0440 Set (Replace Fuel Tank Evaporative Emissions Control System (EVAP) Vent Solenoid Harness) Models: 2000-2002 Chevrolet Cavalier2000-2002 Pontiac Sunfire ConditionSome customers may comment that the SES light is/was illuminated.A technician may find DTC P0440 is stored in the PCM.CauseThe EVAP solenoid harness may be misrouted around the rear antilock brake (ABS) wire harness causing a chaff/damage to the EVAP vent solenoid harness, setting DTC P0440.CorrectionFollow the service procedure below to diagnose and correct this condition.1. Install a Tech 2 scan tool and select the appropriate vehicle. Verify that a DTC P0440 is stored in the PCM. 2. Raise the vehicle on a hoist. Refer to Lifting and Jacking the Vehicle in General Information (SI Document ID # XXXXX).



Locate and inspect the EVAP vent solenoid harness (3) routing. The harness may be routed below the ABS wiring harness (4) at the right rear corner of the fuel tank, causing stress on the EVAP solenoid harness (3).





4.Disconnect the EVAP vent solenoid harness (3) from the EVAP vent solenoid (2) and connector C313 (1). Discard the EVAP vent solenoid harness (3).

5.Connect the new EVAP vent solenoid harness (3), P/N 22687059, to the EVAP vent solenoid (2), route the harness above the rear ABS harness (4) and connect the EVAP vent solenoid harness (3) to connector C313 (1).

6.Lower the vehicle.

7.Clear the DTC's with the Tech 2 scan tool.

If all of the wires are good you will want to check for any leaks in the evap system.

Hope helps.

This indicates that a part of the EVAP control system is no longer fuctioning correctly. The EVAP system consists of many parts, including (but not limited to) the gas cap, fuel lines, carbon canister, purge valve, and other hoses. The (EVAP) emission control system prevents the escape of fuel vapors from a vehicle's fuel system. Fuel vapors are routed by hoses to a charcoal canister for storage. Later, when the engine is running a purge control valve opens allowing intake vacuum to siphon the fuel vapors into the engine.

A code P0440 could mean one or more of the following has happened:
The gas cap is not installed or working properly
The purge solenoid has failed
The canister is plugged and not working properly

With a P0440 OBD-II trouble code, diagnosis can be tricky at times. Here are some things to try:
Remove and reinstall the gas cap, clear the code, and drive for a day and see if the codes come back.
Inspect the EVAP system for cuts/holes in tubes/hoses
Inspect for damaged or disconnected hoses around the Evap purge solenoid
Check and/or replace the sensor
Check and/or replace the purge valve
Have a professional use a smoke machine to detect leaks

Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

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Hi Becca:
P0301 Code - Cylinder #1 Misfire Detected
A P0301 code means that the the car's computer has detected that one of the engine's cylinders is not firing properly. In this case it's cylinder #1.

Symptoms may include:
the engine may be harder to start
the engine may stumble / stumble, and/or hesitate
other symptoms may also be present

A code P0301 may mean that one or more of the following has happened:
Faulty spark plug or wire
Faulty coil (pack)
Faulty oxygen sensor(s)
Faulty fuel injector
Burned exhaust valve
Faulty catalytic converter(s)
Running out of fuel
Poor compression
Defective computer

Possible Solutions:
- If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.
- If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.


P0440 Code - Evaporative Emission Control System Malfunction
This indicates that a part of the EVAP control system is no longer fuctioning correctly. The EVAP system consists of many parts, including (but not limited to) the gas cap, fuel lines, carbon canister, purge valve, and other hoses. The (EVAP) emission control system prevents the escape of fuel vapors from a vehicle's fuel system. Fuel vapors are routed by hoses to a charcoal canister for storage. Later, when the engine is running a purge control valve opens allowing intake vacuum to siphon the fuel vapors into the engine.

You likely won't notice any drivability problems.

A code P0440 could mean one or more of the following has happened:
The gas cap is not installed or working properly
The purge solenoid has failed
The canister is plugged and not working properly

With a P0440 OBD-II trouble code, diagnosis can be tricky at times. Here are some things to try:
Remove and reinstall the gas cap, clear the code, and drive for a day and see if the codes come back.
Inspect the EVAP system for cuts/holes in tubes/hoses
Inspect for damaged or disconnected hoses around the Evap purge solenoid
Check and/or replace the sensor
Check and/or replace the purge valve
Have a professional use a smoke machine to detect leaks

Other EVAP DTCs: P0440 - P0441 - P0442 - P0443 - P0446 - P0453 - P0455 - P0456-

Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa, have a nice day.

2003 GMC Envoy has a problem with the gas tank. The plastic tank cracks at the filler neck inlet, causing some gas leakage and code P0440. GMC replaces gas tanks for free (up to 160?).

p0440 code means that the evap system has a leak. This could be caused by a bad or improperly installed gas cap. Either that or the purge solenoid has failed or the canister is plugged and not working properly.