Hello guys, back again with issues with the car.

So, the car has randomnly popped code P0440 1 of 2 and 2 of 2. I have been searching around and only thing I get is that the gas cap needs to be tightened or replaced and some valve on top of the gas tank.

Can anyone verify that is what it means? Why that there is two codes of the same thing.

Thanks guys, I know I will figure this out from you guys!

 

Which year? This should help:

Document ID# 794651
2002 Chevrolet Camaro


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DTC P0440
System Description
The control module tests the evaporative emission (EVAP) system for a large leak. The control module monitors the fuel tank pressure (FTP) sensor signal to determine the EVAP system vacuum level. When the conditions for running are met, the control module commands the EVAP canister purge valve OPEN and the EVAP vent valve CLOSED . This allows engine vacuum to enter the EVAP system. At a calibrated time, or vacuum level, the control module commands the EVAP canister purge valve closed, sealing the system, and monitors the FTP sensor input in order to determine the EVAP system vacuum level. If the system is unable to achieve the calibrated vacuum level, or the vacuum level decreases too rapidly, this DTC sets.

The following table illustrates the relationship between the ON and OFF states, and the OPEN or CLOSED states of the EVAP canister purge and vent valves.

Control Module Command
EVAP Canister Purge Valve
EVAP Canister Vent Valve

ON
Open
Closed

OFF
Closed
Open


Conditions for Running the DTC
DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0125, P0443, P0449, P0452, P0453, P1106, P1107, P1112, P1114, P1120, P1220, or P1221 are not set.
The ignition voltage is between 10-18 volts.
The barometric pressure (BARO) is more than 75 kPa.
The fuel level is between 15-85 percent.
The engine coolant temperature (ECT) is between 4-30°C (39-86°F).
The intake air temperature (IAT) is between 4-30°C (39-86°F).
The start-up ECT and the IAT are within 9°C (16°F).
The vehicle speed sensor (VSS) is less than 121 km/h (75 mph).
Conditions For Setting the DTC
The EVAP system is not able to achieve or maintain vacuum during the diagnostic test.

Action Taken When the DTC Sets
The control module will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test ran and failed.
The control module will store conditions which were present when the DTC set as Freeze Frame and Failure Records data.
Conditions for Clearing the MIL/DTC
The control module will turn the malfunction indicator lamp (MIL) OFF during the first consecutive trip in which the diagnostic has been run and passed.
A last test failed (current DTC) clears when the control module turns OFF the MIL.
The history DTC will clear after the control module runs and passes 40 consecutive warm up cycles with no failure.
The DTC can be cleared by using a scan tool.
Diagnostic Aids
Use the J 41413 EVAP Pressure/Purge Diagnostic Station in order to pressurize the EVAP system to aid in locating intermittent leaks. Move all EVAP components while testing with the J 41416 Ultrasonic Leak Detector.
A temporary blockage in the EVAP canister purge valve, purge pipe or EVAP canister could cause an intermittent condition. To repair a blockage in the EVAP system refer to Evaporative Emission (EVAP) System Cleaning .
Reviewing the Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.
Test Description
The numbers below refer to the step numbers on the diagnostic table.

This step is used to verify if a leak is present.

This step verifies proper operation of the fuel tank pressure (FTP) sensor.

This step tests the EVAP canister purge valve for a restriction or blockage.

DTC P0440 Step
Action
Values
Yes
No

Schematic Reference: Evaporative Emissions (EVAP) Hose Routing Diagram

1
Did you perform the Diagnostic System Check-Engine Controls?
--
Go to Step 2
Go to Diagnostic System Check - Engine Controls

2
Does the scan tool indicate DTC P0443 or DTC P0449 are also set?
--
Go to Diagnostic Trouble Code (DTC) List
Go to Step 3

3
Inspect the evaporative emission (EVAP) system for the following conditions:
Loose, missing, or damaged service port schrader valve
Loose, incorrect, missing, or damaged fuel fill cap
A damaged EVAP canister purge valve
Raise the vehicle on a hoist. Refer to Lifting and Jacking the Vehicle in General Information.
Inspect the EVAP system for the following conditions:
Disconnected, improperly routed, kinked, or damaged EVAP pipes and hoses
A damaged EVAP canister vent valve or EVAP canister
Did you find and correct the condition?
--
Go to Step 18
Go to Step 4

4

Important
The following steps require the J 41413 EVAP Pressure/Purge Diagnostic Station and the J 41415 Fuel Fill Cap Adaptor .

Always zero the EVAP pressure and vacuum in H2O gages on the EVAP pressure diagnostic station before proceeding with diagnosis.


Install the J 41415 .
Connect the J 41413 and the vehicle fuel fill cap to the J 41415 .
Turn ON the ignition, with the engine OFF.
With the scan tool, seal the EVAP system.
With the J 41413 , pressurize the system to the specified value.
Rotate the EVAP pressure/purge diagnostic station rotary switch to the OFF/HOLD position. Monitor the pressure gage for 1 minute.
Did you obtain and hold the specified value?
5 in H2O
Go to Step 5
Go to Step 7

5
Compare the EVAP pressure/purge diagnostic station value to the scan tool fuel tank pressure (FTP) sensor value.

Does EVAP pressure/purge diagnostic station value measure near the scan tool value?
--
Go to Step 6
Go to Step 11

6
Monitor the pressure gage on the J 41413 .
Disconnect the EVAP purge pipe from the EVAP purge valve.
Does the EVAP system pressure decrease?
--
Go to Step 8
Go to Step 9

7
With the J 41413 , continuously pressurize the EVAP system.

Important
It may be necessary to partially lower the fuel tank to inspect components located in the upper portion of the tank.


With the J 41416 Ultrasonic Leak Detector, inspect for leaks in the following locations:
The EVAP system purge pipe--Refer to Evaporative Emission (EVAP) Hoses/Pipes Replacement - Engine/Chassis .
The EVAP vapor pipe--Refer to Evaporative Emission (EVAP) Hoses/Pipes Replacement - Canister/Fuel Tank .
The EVAP vent hose/pipe--Refer to Evaporative Emission (EVAP) Canister Vent Valve Replacement .
The fuel fill pipe/hose and fuel fill cap--Refer to Filler Tube Replacement .
The EVAP canister--Refer to Evaporative Emission (EVAP) Canister Replacement .
The EVAP canister vent valve--Refer to Evaporative Emission (EVAP) Canister Vent Valve Replacement .
The EVAP canister purge valve--Refer to Evaporative Emission (EVAP) Canister Purge Valve Replacement .
The fuel sender assembly and/or seal--Refer to Fuel Sender Assembly Replacement .
The fuel tank pressure (FTP) sensor seal--Refer to Fuel Tank Pressure Sensor Replacement .
The fill limiter vent valve, pressure relief valve, rollover valve, or fuel tank--Refer to Fuel Tank Replacement .
Did you locate and repair the system?
--
Go to Step 18
Go to Diagnostic Aids

8
Attach a vacuum gage to the purge pipe port of the EVAP purge valve.
Start and idle the engine.
Command the EVAP purge valve to 50 percent with a scan tool.
Does the vacuum gage show vacuum more than the specified value?
10 in H2O
Go to Intermittent Conditions
Go to Step 12

9
Monitor the pressure gage on EVAP pressure/purge diagnostic station.
Disconnect the EVAP purge pipe from the EVAP canister.
Does the EVAP system pressure decrease?
--
Go to Step 14
Go to Step 10

10
Monitor the pressure gage on EVAP pressure/purge diagnostic station.
Disconnect the EVAP vapor line from the EVAP canister.
Does the EVAP system pressure decrease?
--
Go to Step 17
Go to Step 13

11
Monitor the FTP voltage with a scan tool.

Is the FTP voltage more than the specified value?
4.3 V
Go to DTC P0453
Go to Step 15

12
Inspect the vacuum source to the EVAP purge valve for the following conditions:
Blockage
Cuts
Disconnects
Repair as necessary.
Did you find and correct the condition?
--
Go to Step 18
Go to Step 16

13
Repair for a pinched or obstructed EVAP vapor pipe.

Did you complete the repair?
--
Go to Step 18
--

14
Repair the restriction in the EVAP purge pipe. Refer to Evaporative Emission (EVAP) System Cleaning .

Did you complete the repair?
--
Go to Step 18
--

15
Replace the FTP sensor. Refer to Fuel Tank Pressure Sensor Replacement .

Did you complete the replacement?
--
Go to Step 18
--

16
Replace the EVAP purge valve. Refer to Evaporative Emission (EVAP) Canister Purge Valve Replacement .

Did you complete the repair?
--
Go to Step 18
--

17
Replace the EVAP canister. Refer to Evaporative Emission (EVAP) Canister Replacement .

Did you complete the repair?
--
Go to Step 18
--

18
Turn ON the ignition, with the engine OFF.
Command the EVAP vent valve ON with a scan tool.

Important
Do not exceed the specified value in the step. Exceeding the specified value may produce incorrect test results.


Pressurize the EVAP system to the specified value with the J 41413 .
Place the control **** on the J 41413 to the OFF/HOLD position.
Monitor the EVAP system pressure on the J 41413 for 5 minutes.
Does the scan tool indicate that the Service Bay Test passed?
5 in H2O
Go to Step 19
Go to Step 7

19
Monitor the pressure gage on the J 41413 .
Command the EVAP purge valve to 50 percent.
Does the EVAP system pressure decrease?
--
Go to Step 20
Go to Step 9

20
With a scan tool, observe the stored information, Capture Info.

Does the scan tool display any DTCs that you have not diagnosed?
--
Go to Diagnostic Trouble Code (DTC) List
System OK

 

Your replying with great info but its flying over my head, haha... I was hoping for my of a straight forward answer but if this is it, I guess it might have to do. Thanks again.

 

The EVAP system pulls gas vapors from the gas tank and throws them into the air intake of the engine when there's too much pressure in the tank. It also sucks in air when the gas tank pressure is too low.

Jack the back driver side wheel up on a stand and remove the plastic plate behind that wheel. There's a black canister behind there with (should be) 3 hoses leaving from it. That is the EVAP Canister. If there are any visible cracks or hoses not connected, that's your problem. You won't be able to check the entire length of the hoses, but if they look rotten or cracked, replace them.

Under the hood, there are two electrical components to this system (solenoid and vent valve). On the 3.8L V6 Engine, both are on the passenger side of engine (what engine do you have?).

The solenoid (on the 3.8L it's toward front of car) has two hoses attached. One goes to the throttle body, and the other to the vent valve. Check these hoses.

The vent valve (a little further back on the 3.8L) has two hoses attached across from each other, and one valve at a 90 degree angle that should be open to the atmosphere. If the third connector is plugged, unplug it. One of the hoses goes to the solenoid and the other wraps around the engine and follows the fuel lines back to the canister. This hose can be followed under the car on the driver side all the way back. Check all of these hoses and connectors for wear.

It's POSSIBLE that this code could be thrown by a vacuum leak at the engine, but that usually throws a different code first. It's also possible that it could be a fault in any of those three components (canister, solenoid, or vent valve). It's also possible that it could be a leaking gas tank (very rare). Check the cheapest things first always (in this case, rubber hoses). With the addition of alcohol to gasoline, rubber hoses deteriorate a LOT faster than they used to.

 

and for kicks and giglles replace your gas cap with a factory oem gas cap the locking caps often do not seal properly and this is a common code thrown for them but what nnew said above me is pretty much dead on

 

Yeah, I forgot the gas cap. LOL, that should be the FIRST thing you check. If the seal on the gas cap is cracked even a tiny bit, it can throw any of the EVAP codes.

Edit: Check this link for more info if you're still confused.
http://www.obd-codes.com/p0440

 

Just went to the dealership for a new AC Delco gas cap and replaced it. I could of gotten one from O'Reillys but I wanted to keep everything close to OEM as possible with the Camaro.

So, replaced the gas cap, started the car and bam! No more check engine light! Thank god!

Thanks for the help guys. I will check back when I fill up the tank and see if it comes back.

 

P0449 will not show for bad gas cap. P0449 is strictly a 12 v check on the Evap solenoid circuit. The wiring harness has two wires White (or brown w/white stripe) and pink. White is always at 12v. When the module tests, a transistor in the control module switches the ckt to grnd which activates the solenoid. There are only four things that can cause the engine light for a P0449 fault and they are 1. Bad or open solenoid, 2. wire from soelnoid to module (pink_ shorted to ground), 3. Bad (fried) module and 4. 12 volts not coming to the solenoid (white wire)
The most common cause is solenoid went bad. Ohm across it and make sure it isn't open circuit. If it is open, it is bad. They usually last around 2 years and don't cost much. Cracked hoses will not yield a P0449 either.

 

Thanks for reviving a dead three-year old thread sir.