NEED HELP P0440 code popped up again

AzTruckGuy

Original poster
Member
Dec 1, 2015
501
scottsdale, az
Ok after fixing the Trailblazer with a pretty good amount of parts and the dealer replacing the fuel tank under warranty, driving this morning the SES light popped up and I took it over to Auto Zone to get scanned. I thought my P0440 code days where over, go figure I put LEDS in my dash and the SES is jealous since its not the main bitch ass light anymore ha ha

So I checked the lines at the throttle body, its tight
Thorttle body.JPG

I checked the purge valve on the front the engine that was replaced recently, all lines are tight and not loose

Purge Valve.jpg

I check the tank that was replaced by the dealer and everything looks fine, no leaks and hoses are tight to connections
Fuel Tank.JPG

What gives? The Trailblazer is running the smoothest since I got it and the gas seems to be lasting longer than before....Any ideas? I don't want to start throwing money at parts that may not need to be replaced. It also should be noted gas is on its last 1/4 before fill up.
 
Last edited:

Mooseman

Moderator
Dec 4, 2011
25,325
Ottawa, ON
How old is the gas cap?
 

MAY03LT

Member
Nov 18, 2011
3,420
Delmarva
Evap leaks can be a real pita because the tools needed to properly test the system are pricey. So we're kinda limited to visual inspections and statistics. Did you check the gas cap o ring for cracks? Hows everything look around the canister/vent valve?
 

AzTruckGuy

Original poster
Member
Dec 1, 2015
501
scottsdale, az
Evap leaks can be a real pita because the tools needed to properly test the system are pricey. So we're kinda limited to visual inspections and statistics. Did you check the gas cap o ring for cracks? Hows everything look around the canister/vent valve?

How old is the gas cap?

Gas Cap is prob original I assume ... I checked and found these

GasCapcrack.JPG GasCapcracks.JPG

The Charcoal canister area looks fine, connections are all tight, no leaks

Canister.JPG Canisterfittings.JPG

IMG_2096.JPG
 

Mooseman

Moderator
Dec 4, 2011
25,325
Ottawa, ON
I'd change the cap. Fairly cheap and easy. The tank and its vents are OK since they are new as they come with the tank. If a line/hose was broken, you would think the dealer would have said something or screwed up and forgot to hook one up on top.

Better to get an ACDelco and it comes with the tether.
 

AzTruckGuy

Original poster
Member
Dec 1, 2015
501
scottsdale, az
I'd change the cap. Fairly cheap and easy. The tank and its vents are OK since they are new as they come with the tank. If a line/hose was broken, you would think the dealer would have said something or screwed up and forgot to hook one up on top.

Better to get an ACDelco and it comes with the tether.

Just ordered this one https://www.amazon.com/gp/product/B000C9R1D8/?tag=gmtnation-20

Yeah I noticed that a line wasn't hooked up to that connection on the tank, when I was working on the vehicle. I tried to pull one of the lines down, but they didn't want to go there. The dealer prob doesn't like me much since it cost them over $2k for my rental, after a lawyer wrote them a nice letter on how I was driving around with a leaky gas tank
 

Mooseman

Moderator
Dec 4, 2011
25,325
Ottawa, ON
Costs them nothing. The bill goes to their corporate office for payment.
 

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