Code P0440

YOURMINKY

MEMBER
1997 NISSAN SENTRA
AUTOMATIC
115,000 MILES

My car listed above GXE 1.6 automatic transmission started to get both P0446 and P0440 codes a few months ago. I bought a new gas tank filler cap and the P0446 code went away. I am getting only P0440 code every month now. I know the new cap is holding vacuum because when I unscrew it, air hisses in to fill the vacuum. What could be causing P0440 and how to fix it?

Sunday, May 6th, 2018 AT 5:52 PM

3 Replies

RELLY999

MECHANIC
21 POSTS

Hello YOURMINKY.

How are you doing? Looks like that you replaced everything to resolve the P0446 and P0440 issue. Good to know that the P0446 is eliminated already. Now about the P0440 popping up, I strongly suggest that you replace the EVAP canister. It can be worn out or faulty that is why it is registering on the car's ECU. Hope this resolves the issue and keep us posted. Thank you and have a good one!

Regards,

Relly

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Monday, May 7th, 2018 AT 3:02 AM

YOURMINKY

MEMBER
106 POSTS

Thanks for your reply. I could not figure out the location of the EVAP canister from the diagram. Can you please post an actual photo?
Is this something that a technically inclined car owner can do?
Before changing the canister, should I check the hoses or smoke test it?
Thanks again.

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Tuesday, May 8th, 2018 AT 7:19 PM

KEN L

MASTER CERTIFIED MECHANIC
50,088 POSTS

The code indicates there is a large leak int he EVAP system so I would start with a smoke test. I have seen the charcoal canister cause this issue which is back near the rear of the car.

Check out the diagrams (below). Please let us know what happens.

Cheers, Ken

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