This issue started 6 months after my family purchased a 16 Yukon new, but didnt realize it until recently since it is a hand me down from my dad. Its a 2004 5.3 GMC Yukon SLT with 120k miles. Anyways, I popped in a cheap ECU reader and it gave me a P0449 code for the evap system. This was a stored code and I did not have a check engine light, people said it’ll recheck under really specific conditions so that’d explain why. I ended up researching on youtube, here and other forums to come up with a solution. I was able to achieve that with the parts above and by cleaning the pipes between all three parts with compressed air (I went to a friend’s shop to do this, since I didn’t find anything that told me what to disconnect to not have pellets go into the tank).
What you’ll need is:
A spanner with 8 mm and 13 mm extensions to remove the bolts for the purge valve and charcoal canister respectively.
A flathead screw driver to wedge between pipe fittings to get them to come loose.
I didnt need a 2/4 point lift to swap out the parts but it doesnt hurt to have more space. I use jack stands to give me a bit more leeway.
Vent Solenoid:
I followed this video:
All you need here is a flathead screwdriver.
I didn’t bother with the relocation kit since this is an inexpensive part and this is my first time ever working on a car and it looked complicated (my dad put up the jack stands for me, just saying)
After I replaced this part, which most people said would be the culprit, I still had fueling issues so I did the purge valve next. However, I’m sure this was an issue since the filter disintegrated in my hand and it was full of dust.
Purge Valve:
I followed this video:
You’ll need a spanner and an 8mm extension here.
This didnt end up fixing it, so I did the charcoal canister next. The part itself seemed fine, but it was an inexpensive part anyways.
Charcoal Canister:
I partially followed this video:
You’ll need a flathead screwdriver, spanner and a 13mm extension here.
After replacing this, the car ended up filling up normally, which was great. Although, a lot of forum members here and elsewhere mentioned dropping the tank and cleaning the lines to make sure it stays that way and not to overfill. Noted on the latter, not a clue what to do on the first one so I took it to my friend’s shop and he had to drop the tank which I’d be too anxious to do. I also asked him to check the ECU to see if the fuel tank pressure sensor (part #16238399) was bad, but it was working as expected. If you still have issues after that I’d look into the sensor since it could stop vents fom engaging.
I hope this helps!
