Ready to Junk it; 2007 Yukon 5.3 EVAP

[juicyroot]

OMG I replaced the complete EVAP on this truck and still getting p0446... I replaced the vapor canister vent valve, solenoid, (upgraded version) charcoal canister and stlll p0446.
Oh and I forgot to mention, I dropped the fuel tank and blew all the EVAP lines out and none were clogged.
If you have experienced this or have any ideas what's going on please inform.
Replaced gas cap probably 3 months ago cause information kept saying loose gas cap...
And the CEL doesn't come on for this code. CEL works because it lights up when I start the truck. I check the codes with my cheap OBD scanner, lol.
TIA my friends

 

[mikez71]

Maybe a leak in the filler tube, tank or evap plumbing?
Might be some way to check with compressed air into filler tube? not sure

 

[West 1]

Evap system issues usually show up with a smoke test. You hook the smoke machine up to your intake system and blow smoke at 3-5 psi into the system and then watch to see where the smoke is leaking out. EVAP issues can be hard to track down but a smoke test usually gives you answers in 15 minutes. Smoke machines are on Amazon for less than $100 or you can make your own.

 

[07burban88]

is the check engine light on while driving? or just codes in the ecu?

 

[07burban88]

they may be perminate codes that done clear with a scanner. the ecu removes them after so many drive cycles. if nothing is listed as stored/confirmed or pending, your good

 

[strutaeng]

You got a buddy with HP Tuners?

 

[OR VietVet]

You daid you replaced the complete EVAP and then say you just blew the lines out. HUH!

I get that you are frustrated but C'mon man!

By the way, there is no code that says replace the gas cap. It will say "possible reasons for code" and then list items in the EVAP system that can set that code.

 

[juicyroot]

is the check engine light on while driving? or just codes in the ecu?

CEL is not on. Only in the ECU I'm guessing. I erased all codes after new evap installment

 

[juicyroot]

You got a buddy with HP Tuners?

No

 

[Fless]

Here's the diagnostic path for that code, but when you hit the link be sure to verify that I selected the correct vehicle, or navigate to yours:

P0446 — 2007 GMC Yukon 2WD V8-5.3L Service Manual | Operation CHARM

Detailed repair manual for the 2007 GMC Yukon 2WD V8-5.3L.

charm.li

A smoke test (as @West 1 suggested) can help with diagnosis.

A purge and seal test might show a clue or two.

There is also a thread on here about what the fuel tank pressure sensor readings should be. A bidirectional scan tool that can read live data would be a useful tool.

Lastly, read the thread below and note the informative video in post #3 (GoTech Wells CounterPoint linked below):

Fuel Tank Pressure Off - SOLVED

Got the P0446 code on a 2006 Tahoe so started the Evap Mystery Game. But since this truck is new to me recently and I haven't done any evap system work on it yet just decided to replace the 3 main parts that go wrong. Purge valve, Vent Valve, and the canister. Bench tested the solenoids and...

www.tahoeyukonforum.com

 

[juicyroot]

You daid you replaced the complete EVAP and then say you just blew the lines out. HUH!

I get that you are frustrated but C'mon man!

By the way, there is no code that says replace the gas cap. It will say "possible reasons for code" and then list items in the EVAP system that can set that code.

I guess you didn't comprehend what I said HUH
I BLEW ALL THE LNES OUT ON THE TANK AND NONE WERE CLOGGED

 

[setha8]

CEL is not on. Only in the ECU I'm guessing. I erased all codes after new evap installment

Then you are good! You are probably seeing the "archive" code, which means it's not an active code. Mine is the same way after I cleared the lines. I can see that the code once active, but is no longer active. If the code comes back then you will need to do a smoke test like someone mentioned above.

I actually do have a small leak still, and my CEL does come back on at about 1/3 fuel level when it runs the test. I finally took the time to smoke test it to find exactly where the leak is.

 

[juicyroot]

Here's the diagnostic path for that code, but when you hit the link be sure to verify that I selected the correct vehicle, or navigate to yours:

P0446 — 2007 GMC Yukon 2WD V8-5.3L Service Manual | Operation CHARM

Detailed repair manual for the 2007 GMC Yukon 2WD V8-5.3L.

charm.li

A smoke test (as @West 1 suggested) can help with diagnosis.

A purge and seal test might show a clue or two.

There is also a thread on here about what the fuel tank pressure sensor readings should be. A bidirectional scan tool that can read live data would be a useful tool.

Lastly, read the thread below and note the informative video in post #3 (GoTech Wells CounterPoint linked below):

Fuel Tank Pressure Off - SOLVED

Got the P0446 code on a 2006 Tahoe so started the Evap Mystery Game. But since this truck is new to me recently and I haven't done any evap system work on it yet just decided to replace the 3 main parts that go wrong. Purge valve, Vent Valve, and the canister. Bench tested the solenoids and...

www.tahoeyukonforum.com

Thank you
I was thinking fuel tank pressure switch but then the fuel pump was replaced like 9 months ago

 

[Fless]

Easy enough to read the fuel tank pressure sensor voltage with a decent scanner, and compare it to what it should be, say, at atmosphere, and what it does when the tank is pressurized. Mike does a good job of explaining that in the video. Eric O (YouTube - South Main Auto) has also done a video or two where he does the test, and at least one was the tank pressure sensor.

 

[Fless]

Note that the evap test runs only under certain conditions: cold start, ambient temp within 11(?) deg of engine coolant temp, fuel tank level between 1/8 and 7/8, and a few others. So it won't run on a warm start and won't run every cold start.

 

[mikez71]

I guess you didn't comprehend what I said HUH
I BLEW ALL THE LNES OUT ON THE TANK AND NONE WERE CLOGGED

I took his comment to mean, you didn't do all that much to be frustrated to the point of wanting to junk your vehicle.?

Looks like some good videos, keep us posted.

 

[Fless]

To add: evap issues can be frustrating, but these are relatively simple systems. Going through the diagnostic tests can help identify what condition or part is causing the failure. Soldier on!

 

[setha8]

I took his comment to mean, you didn't do all that much to be frustrated to the point of wanting to junk your vehicle.?

Looks like some good videos, keep us posted.

No kidding! I spend two days clearing the line between purge valve and the front of the fuel tank. Soaked it in B12, blew back and forth, back and forth, once clear, then changed canister, vent valve, purge valve, dropped the tank and blew every line out on that end of the system. And even then I wasn't at the "junk the car" stage, lol.

 

[juicyroot]

I took his comment to mean, you didn't do all that much to be frustrated to the point of wanting to junk your vehicle.?

Looks like some good videos, keep us posted.

Maybe so but I've had this vehicle little over a year and I've had a ton of issues with it. It's been a money pit!

 

[SpareParts]

Seems most are but after all the issues are fixed that has been neglected you are gonna LOVE IT!!