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Discussion Starter #1
P0449 - Frustrated • Which Part# ?


So...I have the code that everyone just hates...the ‘ol P0449. Now, I’ve replaced the evap canister up behind the rear passenger tire, plus the harness, and the associated sensor, and I invariably still have the P0049 emissions code [even after clearing the code(s)]...It keeps coming back.

Now, I dunno if this (see attached photo and url link at end of this post) MAY have anything to do with it, but what do ya’ll think ?

The flapper that was riveted must be lodged in the filler tube or the tank itself as it had nowhere to go but down.

Do y’all think that the missing flapper is creating my P0049 CEL code ?

I know one thing fer sure...when I stop to put gas in the tank, I have to wait about 30-60 seconds for the pressure to bleed off or the gas comes back and sprays all over.

Or, is it a nominal effect and maybe I need to replace the ‘Fuel Pressure Sensor’ ontop of the gas tank ?

I’m beyond my wits with this freakin’ error. As I say, I’ve replaced the Evap Canister and the associated sensor under the hood.

I’ll check again for splits in hosing and poor electrical connections.

Maybe I got a bad out of box new unit ?

Also, I’ve noticed that pronounced ‘clicking’ sound under the hood. It’s not the A/C compressor; I think it’s the Evap Solenoid/Sensor. Is this normal ? It sure seems alot louder and pronounced than it’s ever been.

Lastly, I’ve replaced the fuel cap. HOWEVER, I’ve read on this forum that I should try to get the cap with the ‘White’ lettering Vs. the ‘Blue’ lettering. Is this true ? I mean maybe it’s as simple as replacing the gas cap yet a 3rd time ?

Which part# should I try this time ?

This link shows 19329627 which replaces 92221384.


And...this link shows part# 214-2324 which replaces 214-2147.


I look forward to any and all opinions and feedback.

Pictures of Missing Flapper Here:

Best Regards,

Call/Text Me: (610) 842-7905
Email Me: [email protected]

Missing Fuel Flapper Photo:


Premium Member
4,417 Posts
I'm not sure of the exact reason for the spring loaded flap (about 1 to 2" down the fuel pipe lip), that are installed on some of the older cars. For sure the G8's (as made for the US), did not come with one. I have a 99 beater Toyota an *it* does have one. The G8 an my 11 GMC pickup do not. When they still had leaded gas, they had to design some type of protection to prevent leaded gas from being pumped into a car that was designed to run on unleaded gas only. The larger diameter gas nozzles (that leaded gas used) wound no longer be able to fit into the unleaded cars fill pipe. Nowadays the cars fill pipe is sized to accept *only* unleaded gas from gas pump fill nozzles that have also been resized. As a side note, a lot of new cars no longer even have fill pipe caps. They have been designed (some way) to seal off the pipe opening once the nozzle has been removed.

That code you still get, says that the canister vent valve does not agree with what the ECM has commanded it to do (as in open or closed). Your post reads like you changed the canister itself as well as the purge valve on the engine. Those items (to me) have no bearing on that P0449 code. If the GM service department were to check that out, they could command that vent valve to open an close over an over, an the computer would tell them if it opened an closed correctly as requested (for a nifty price). For you to check that same vent valve solenoid out, you'd have to improvise with some wire testing leads used between the solenoid and its connector. If the new canister also came with a new vent valve solenoid, you may have wiring problems to it. For sure the vent valve is supposed to be in the open position when fueling the car. As gas goes in, air pressure starts to build along with the fuel vapor, that stuff needs to go somewhere. The gas vapor gets trapped in the charcoal canister an stores it (until the ECM tells the purge valve to pulse open/closed, an pull that trapped fuel vapor out of the canister for use in the running engine), while the clean air under some pressure, continues out thru the vent valve to the atmosphere. I'm thinking that *IF* the vent valve failed to open, it might make for a hard time filling the tank as a by product.

2,943 Posts
I could swear mine has a flapper. I'll have to look.

That corrugated looking tube is new. I have an 08 solenoid (for sale, coincidentally) and there is no tube.

Looking at the listing for it, it requires also getting a new connector...?


317 Posts
I see Cortex tune in your signature...another way to relieve all that frustration is to go get a dyno tune or buy a copy of HP Tuners and just have the system turned off. Never have to worry about it again.
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