Question about 2005 Chevrolet Tahoe

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My 2005 Tahoe has engine light codes P0449 & P0455. What should I replace first?

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The PCM has determined that a malfunction exists in the electrical circuit for the vent valve/solenoid in the evaporative emission control system.

Probable Causes
1- Purge or vent solenoids defective
2- Check connevtor and wiring
3- Fuel saturated vapor canister
4- Failed EVAP vent solenoid

Posted on Aug 24, 2010


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Jan 07, 2016 | 2004 Chevrolet Chevrolet Impala

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My check eng. light came on and I had it checked and the two codes p0455 &p0449 showed up, what should I do about this?

P0455 stands for evap emissions detection leak and p0449 stands for evap emissions vent control circuit. You should go to a parts store and see if your able to purchase and install. Best of luck!

Feb 27, 2012 | 2007 Buick LaCrosse CXL Sedan

1 Answer

2005 chevy 1500 silverado eng. light on ran code p0455 and p0449 how to fix the problem. and how much work it takes. thanks STEVE.

P0449 is the evap vent valve solenoid circuit malfuntion.
P0455 is an evap gross leak
Perhaps the gross leak code has to do with the vent valve. Find the vent valve. It should be near a rectangle evap canister. Maybe under the bed. The small vent line from the fuel tank will go to it. The solenoid is near the cansiter. With the key off the valve will be open. With the key on it should be closed. You may try disconnection the hose and blow through it with both key off and on and see if air will pass through. If the valve has died and is stuck open, that can be the huge leak.

If it is not the leak then a smoke machine should be used. Easier than searching the lines for bad o-rings, splits, or whatevers.

Sep 02, 2011 | 2005 Chevrolet Silverado 1500 2WD

1 Answer

I got a '06 Trailblazer, LT series and L6 engine. I got the check engine ON with P0449 and P0455 codes and the MIL On too. I change 2 solenoids (Purge and Vent), clear the codes with mine codes reader...

maybe aftermarket products--------disconnect batt and touch neg and pos cables together-after few minutes reattach and start car-----as long as its runnin fine-cause its just evap emmiss issue

Aug 09, 2011 | Chevrolet TrailBlazer Cars & Trucks

2 Answers

P0449 and P0455 error code 2008 2wd gmc envoy 30,203 miles

P0449 - Evaporative Emission Control System Vent Valve/Solenoid Circuit Malfunction

P0455 - Evaporative Emission Control System Leak Detected (no purge flow or large leak)

Both are refer at EVAP system; other EVAP DTCs: P0440 - P0441 - P0442 - P0443 - P0446 - P0453 - P0455 - P0456

This indicates a fuel vapor leak or lack of purge flow in the EVAP control system. It means a large leak has been detected. 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.

Symptoms: You likely won't notice any drivability problems.
Causes: most likely means one or more of the following has happened:
A loose or improperly affixed gas cap
A non-conforming gas cap (i.e. not factory/original brand)
Other leak or damaged piece in EVAP system

Possible Solutions: the most common repair is to:
Remove and reinstall the gas cap, clear the codes, and drive for a day and see if the codes come back.
Otherwise, replace the gas cap, and/or
Inspect the EVAP system for cuts/holes in tubes/hoses (you may hear a vacuum noise or smell fuel), repair if necessary

Hope helps.

Apr 23, 2011 | 2008 GMC Envoy

2 Answers

I have a 2006 Chevy reported are P0449 and P0455....replaced fuel cap but did not solve problem....what are my next steps without spending tons of money at a dealership? Thanks

There may be an emissions leak but a very common issue is the canister vent valve. Make sure if you contact your local dealership that you have your vehicles vin number available.
  • P0449 - Evaporative Emission (EVAP) Vent Solenoid Control Circuit
  • P0455 - Evaporative Emission (EVAP) System Leak Detected
  • Dec 28, 2010 | 2006 Chevrolet Tahoe

    2 Answers

    What are codes P0455 and P0449 ?

    these are emission system codes p0455 is large leak detected the pcm monitor gas tank pressures to determine if it has a vapor leak and it is detecting a vapor leak larger than .040 of an inch these generally are best diagnosed by a dealer.

    Dec 16, 2010 | 2005 Chevrolet Colorado

    3 Answers

    My check engine light is on and I am getting codes P0449 and P0455. What is this and how do i fix it?

    The p0455 is for a leak concern and if that was the only code I'd say give the cap a shot. However the p0455 is most likely just a side effect of the P0449. The P0449 is a test that is run on the vent solenoid circuit to check the electrical functions in basic terms. The computer is putting out voltage amount X and in a properly functioning circuit it knows it will see voltage amount Y come back. It isn't coming back as what it expects to come back at so there must be something electrically wrong with the vent circuit. And of course if the vent doesn't work you get a large leak. If we are just throwing parts at trucks the logical one for you is a vent valve. Since your Vue is a 2008, most likely there is a good chance that it's covered under the emission warranty which is 5 years.
    Thank you for using fixya. and be safe.

    Jul 07, 2010 | 2008 Saturn VUE

    2 Answers

    Getting codes P0455 and P0449. From what I read,

    The vent solenoid valve has been redesigned to correct the problem you are having. I would recommend purchasing the dealer component.
    I am not aware of any aftermarket parts suppliers.

    Feb 25, 2010 | 2005 Chevrolet Avalanche

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