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I have a 2009 Cobalt Lt 2.2L Now the problem. So for a while I have been getting a clicking noise from inside the car (by glove box) for about 3-5 seconds. It does not do it everytime on startup but occasionally. The check engine light came on and now the car wont pass emissions.

Now with more details. When you hit the recirculation button for the a/c it quits. The code the emissions got was a p0449-Evap emission control system vent valve/solenoid circuit malfunction.

Everything I have seen online shows the valve or solenoid under the hood in engine bay. But this noise like I said is coming from inside the car by glove box.

So has anyone else had this problem and what did it take to fix it. I have seen others mention this but not definite solution. Dealership and one place I called wants $100 just to look at it, so don't want to waste money if not needed.
 

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I think you have 2 seperate problems. You have a problem with your air box, probably a stripped gear or a snapped shaft. The other is an EVAP code P0449. This code means your EVAP valve at the EVAP canister has malfunctionned. Sometimes rodents will chew the wires, so check wires and connections. If these are good change the EVAP solenoid. One sure sign that it's bad is you will have a hard time to refill your gas tank without the nozzle kicking off.

DTC P0449
Circuit Description
A battery voltage is supplied to the evaporative emission (EVAP) canister vent solenoid valve. The control module grounds the EVAP canister vent solenoid valve control circuit to close the valve by means of an internal switch called a driver. The scan tool displays the commanded state of the EVAP canister vent solenoid valve as ON or OFF. The control module monitors the status of the driver. If the control module detects an incorrect voltage for the commanded state of the driver, this DTC sets.




 

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RedX,

If you choose to have your Chevrolet dealership look into this please let me know. You can send us a private message with your name, VIN, phone number, and dealership.

Erica Tiffany
Chevrolet Customer Care
 

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RedX,

If you choose to have your Chevrolet dealership look into this please let me know. You can send us a private message with your name, VIN, phone number, and dealership.

Erica Tiffany
Chevrolet Customer Care
Can't send a private message because I don't have 10 posts on here.
 

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I have the same issue with mine, lots and lots of clicking noises from behind the dash when starting it up. I was told it was relays and such but ive never heard that on any car ive ever owned. Moms LT cobalt does the same thing but not with the same severity.
 

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Well mechanic fixed the first issue and now getting high voltage to pressure switch p0454 and said prob need new ecm so yay me. O and looks like there is an emissions warranty til 80k miles but not the ecm, that's only 36k miles
 

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Well I don't believe it for one second. The mechanic must have disconnected the fuel pressure sensor or maybe just accidently pulled it out of it's seating position. Fixing one code does not cause an other code to pop up.

DTC P0454
System Description
The fuel tank pressure (FTP) sensor measures air pressure or vacuum in the evaporative emission (EVAP) system. The control module supplies a 5-volt reference and a low reference circuit to the FTP sensor. The FTP sensor signal voltage varies depending on EVAP system pressure or vacuum. This DTC will set if the control module detects an intermittent signal from the FTP that would prevent the engine-off small leak test, DTC P0442, from running.

DTC Descriptor
This diagnostic procedure supports the following DTC:

DTC P0454 Fuel Tank Pressure (FTP) Sensor Circuit Intermittent

Conditions for Running the DTC
• DTC P0454 runs only when the engine-off natural vacuum small leak test, P0442, executes.

• This test can run once per engine-off period. The length of the test can be up to 10 minutes.

• A refueling event is not detected.

Conditions for Setting the DTC
If, during the engine-off natural vacuum small leak test, P0442, the engine control module (ECM) detects an abrupt FTP signal change, other than a refueling event, this DTC will set. An abrupt change is defined as a change of 1 inch H2O in the span of 1 second.


Just push on the fuel pressure sensor to make sure it is in all the way. It is just press fit in place and sits just below the EVAP valve solenoid. This is what it looks like.



And this is where it hides....

 

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This is why i dont take my car to mechanics. That vent solenoid litterally takes 2 minutes to change, you reach under the back of the car, disconnect the plug, twist, pull, install new one in reverse order. lol They cost about 16 bucks at your local parts store. Dorman makes the revised design as well.
 
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