EVAP leak - code PO441

ADONIS LANGCAUON

MEMBER
2008 TOYOTA COROLLA
1.8L
4 CYL
2WD
AUTOMATIC
125,000 MILES

I had a PO171 and po441. When I cleaned the MAF, replaced the air filter, and replaced the purge solenoid, the only remaining code is now po441.
I replaced the gas cap, charcoal canister, and checked the fuel pump assembly but the po441 would not disappear.
I built a smoke tester (via DIY mr fusion) and smoke tested by using the vacuum line just before the purge solenoid. The only source of leak I get is from around the gas cap.
Is this leak normal/expected? Should I change the whole filler neck?

3 Replies

ASEMASTER6371

MECHANIC
52,797 POSTS

Good afternoon.

when you said you replace the canister, was it the entire assembly or just the canister?

https://www.2carpros.com/articles/how-emission-control-systems-work

Do you have a scan tool that can do a bay test for the evap system?

This could be an electrical issue but needs to be confirmed.

https://www.2carpros.com/articles/smog-test-inspection-information

I attached a wiring diagram for you to view. I would confirm voltage to all the solenoids and the returns as well to the ECM.

Roy

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Wednesday, April 22nd, 2020 AT 12:34 PM

ADONIS LANGCAUON

MEMBER
2 POSTS

Thank you Roy for answering my question.
I replaced the entire canister assembly.
I don't have a bidirectional scanner to perform the bay test.
Any help on how to perform the electrical test will be appreciated greatly.
Again, thank you.

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Saturday, April 25th, 2020 AT 2:15 PM

ASEMASTER6371

MECHANIC
52,797 POSTS

Okay, at this point, all you can do is check the voltage at the solenoids as I highlighted in my previous posts.

The ECM controls the solenoids to turn on and off. That will require a scan tool to monitor the system.

Roy

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Saturday, April 25th, 2020 AT 2:27 PM