# P0440 code coming back monthly on 1997 Nissan Sentra GXE

**URL:** <https://community.cartalk.com/t/p0440-code-coming-back-monthly-on-1997-nissan-sentra-gxe/116894>\
**Category:** Maintenance/Repairs\
**Tags:** nissan, sentra\
**Created:** [May 7, 2018, 12:46am UTC](https://community.cartalk.com/t/p0440-code-coming-back-monthly-on-1997-nissan-sentra-gxe/116894 "2018-05-07T00:46:25Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![YourMinky](https://avatars.discourse-cdn.com/v4/letter/y/4bbf92/32.png) [@YourMinky](https://community.cartalk.com/u/YourMinky)\
**Post date:** [May 7, 2018, 12:46am UTC](https://community.cartalk.com/t/p0440-code-coming-back-monthly-on-1997-nissan-sentra-gxe/116894/1 "2018-05-07T00:46:25Z")

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My 1997 Nissan Sentra GXE 1.6 automatic transmission started to get both P0446 and P0440 codes a few months ago. I bought a new gas 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 this and how to fix it?

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**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\
**Post date:** [May 7, 2018, 12:53am UTC](https://community.cartalk.com/t/p0440-code-coming-back-monthly-on-1997-nissan-sentra-gxe/116894/2 "2018-05-07T00:53:03Z")

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DTC P0440 indicates a large leak has been detected in the EVAP system

DTC P0446 indicates that there’s a problem with the vent valve circuit of the EVAP system.

If the vent valve doesn’t close when the EVAP system performs its self-test, you get a P0440 code.

Tester.