# 2018 Toyota Prius - Sound help

**URL:** <https://community.cartalk.com/t/2018-toyota-prius-sound-help/162561>\
**Category:** Maintenance/Repairs\
**Tags:** toyota\
**Created:** [April 7, 2020, 1:44am UTC](https://community.cartalk.com/t/2018-toyota-prius-sound-help/162561 "2020-04-07T01:44:42Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![DerrickPetry](https://avatars.discourse-cdn.com/v4/letter/d/bcef8e/32.png) [@DerrickPetry](https://community.cartalk.com/u/DerrickPetry)\
**Post date:** [April 7, 2020, 1:44am UTC](https://community.cartalk.com/t/2018-toyota-prius-sound-help/162561/1 "2020-04-07T01:44:42Z")

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Every once in a while I go into my garage at night and hear a sound similar to air being let out of tires coming from the rear of the car. Of course, the tires never deflate. I would also occasionally hear this on my prior car, a 2006 Corolla. Any idea what this is? Thanks

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**Author:** ![GorehamJ](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/gorehamj/32/24103_2.png) [@GorehamJ](https://community.cartalk.com/u/GorehamJ)\
**Post date:** [April 7, 2020, 2:04pm UTC](https://community.cartalk.com/t/2018-toyota-prius-sound-help/162561/2 "2020-04-07T14:04:03Z")

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My guess would be it is a sound from the fuel vapor management system.

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**Author:** ![VDCdriver](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/vdcdriver/32/30_2.png) [@VDCdriver](https://community.cartalk.com/u/VDCdriver)\
**Post date:** [April 7, 2020, 2:19pm UTC](https://community.cartalk.com/t/2018-toyota-prius-sound-help/162561/3 "2020-04-07T14:19:50Z")

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> [@GorehamJ](#):
>
> My guess would be it is a sound from the fuel vapor management system.

+1  
The Owner’s Manual for my friend’s Rav-4 mentions the “normal” noise from the periodic self-test of the vehicle’s Evaporative Emissions system. That self-test is run after the vehicle has been idle for several hours.

I would be surprised if the Prius Owner’s Manual didn’t mention this situation.  
Has the OP perused that manual?  
🤔

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**Author:** ![PvtPublic](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/pvtpublic/32/13089_2.png) [@PvtPublic](https://community.cartalk.com/u/PvtPublic)\
**Post date:** [April 7, 2020, 4:33pm UTC](https://community.cartalk.com/t/2018-toyota-prius-sound-help/162561/4 "2020-04-07T16:33:31Z")

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> [@VDCdriver](#):
>
> Has the OP perused that manual?

Surely you jest. 🤣