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P0449 Check Engine Light

20streetrod06

Full Member
Joined
Oct 7, 2020
Messages
273
Location
Central IL
as soon as it got real cold here, i had a check engine light pop on the dash, i checked it and its the P0449 "Evaporative Emission System Vent Valve/ Solenoid Circuit"

i remember chasing a similar (maybe identical) code on my Colorado, on it i ended up replacing a part by the fuel tank, as well as a part on the side of the engine block. which part is more likely the culprit on the Avalanche?

On RockAuto i see "round solenoid" and "rectangle solenoid". the round is $107 and includes a rigid hose, the rectangle is $17, and does not have a hose.
 
If there is an option it's never the cheaper one, right???

On the 2nd gen, it's the round solenoid.. I had to replace it already on mine. Wish I could say with certainty on your 2003.

Do you have time to crawl under and check? Today is the day for decent weather, near 50 in central IL! I'm almost sure it is visible without removing the spare tire. While you are there check the fuel filler hose for visible tears, it can cause the same evap code. Also, tighten the fuel cap. The computer can get confused with which part is bad when dealing with slow evap leaks..

Edit, after checking youtube there is a chance it is the rectangle, see a reference video on a suburban here:
 
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I have replaced the Vapor Canister Vent Solenoid on my 2004 Z71 4x4 (173K miles) two or three times with the ACDelco 214-2149 part when emissions error codes were reported, including P0449. It’s a little bit of a hassle to disconnect hose/wiring connectors as I recall, but there are Youtube videos out there to provide guidance. My experience with my truck has been that this emissions error has been a result of a faulty Vent Solenoid, not the Vapor Canister Purge Valve in the front on the engine - but you may need to check for leaks in hoses, etc. I have not encountered drivability issues with these codes, but having to look at the CEL is annoying.

I have also replaced the Vapor Cannister (rectangular box with charcoal material) when the gas pump would shut off prematurely, making it difficult to gas up. Same thing, a little challenging to remove hose connectors.

Good luck.
 
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I have replaced the Vapor Canister Vent Solenoid on my 2004 Z71 4x4 (173K miles) two or three times with the ACDelco 214-2149 part when emissions error codes were reported, including P0449. It’s a little bit of a hassle to disconnect hose/wiring connectors as I recall, but there are Youtube videos out there to provide guidance. My experience with my truck has been that this emissions error has been a result of a faulty Vent Solenoid, not the Vapor Canister Purge Valve in the front on the engine - but you may need to check for leaks in hoses, etc. I have not encountered drivability issues with these codes, but having to look at the CEL is annoying.

I have also replaced the Vapor Cannister (rectangular box with charcoal material) when the gas pump would shut off prematurely, making it difficult to gas up. Same thing, a little challenging to remove hose connectors.

Good luck.
was that the same part number as the one you took off? according to rock auto the one for my '03 is 214-1091.

as you stated, i have also not had any drivability issues, just annoying to see the CEL and scanning it once in a while to make sure its still the only code.
 
ACDelco 214-2149 is the part number that Rock Auto shows, I have purchased, and installed on my 2004 Z71 1500. You can do a visual check on your truck to match your Vent Solenoid with diagrams shown online and confirm you’re purchasing the correct part. Would not fully ensure you have correct part number, but may help.

The Vent Solenoid should be relatively easy to see (but you may need to lower the spare tire to get the visual). Maybe use your phone to snap a photo. Assuming that the Vent Solenoid is the source of your error code, you should be able to replace within an hour or so if you don’t have to fight with the connectors too much. You can clear the error code with a scanner, or if the problem has been corrected, the error code should eventually clear on its own.

Please report back on your end result.
 
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