# 09 focus se code p0451

**URL:** <https://community.cartalk.com/t/09-focus-se-code-p0451/91969>\
**Category:** Maintenance/Repairs\
**Created:** [December 15, 2015, 8:43pm UTC](https://community.cartalk.com/t/09-focus-se-code-p0451/91969 "2015-12-15T20:43:06Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![system](https://global.discourse-cdn.com/cartalk/original/3X/1/d/1d47c66a543aa6c5a7873bb2320858f978ff52ed.png) [@system](https://community.cartalk.com/u/system)\
**Post date:** [December 15, 2015, 8:43pm UTC](https://community.cartalk.com/t/09-focus-se-code-p0451/91969/1 "2015-12-15T20:43:06Z")

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for the last month i have had a code come up as p0451 and it says the fuel tank pressure sensor needs replacement. i cant find it in any repair manuel and my machnic says there is nothing wrong with my fuel system. he did find that my valve cover gasket was leaking, so we replaced that. i was also smelling gas in the car in the mornings so my brother in law replaced the purge valve, smell did go away but the light still on. do you guys have any suggestions?

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**Author:** ![knfenimore](https://avatars.discourse-cdn.com/v4/letter/k/9fc348/32.png) [@knfenimore](https://community.cartalk.com/u/knfenimore)\
**Post date:** [December 15, 2015, 8:58pm UTC](https://community.cartalk.com/t/09-focus-se-code-p0451/91969/2 "2015-12-15T20:58:06Z")

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Try a little vaseline on gas cap seal. You could have evap system smoke cheched.

Common Problems That Trigger the P0451 Code

Defective Fuel Tank Sending Unit  
Defective or damaged Fuel Tank  
Defective Fuel Tank Pressure Sensor, wiring, or computer  
Defective Carbon Canister  
Defective Canister Vent Valve - in some cases

Common Misdiagnoses

Fuel Cap  
Evaporative Purge Valve  
Evaporative Vent Valve

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**Author:** ![system](https://global.discourse-cdn.com/cartalk/original/3X/1/d/1d47c66a543aa6c5a7873bb2320858f978ff52ed.png) [@system](https://community.cartalk.com/u/system)\
**Post date:** [December 15, 2015, 11:11pm UTC](https://community.cartalk.com/t/09-focus-se-code-p0451/91969/3 "2015-12-15T23:11:59Z")

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um… my mechanic already checked those. he said there isnt anything wrong with me fuel system. he did a complete dignostics.

i’ll try the vaseline on the cap but not sure if it will help.

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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:** [December 16, 2015, 3:31am UTC](https://community.cartalk.com/t/09-focus-se-code-p0451/91969/4 "2015-12-16T03:31:27Z")

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The fuel tank pressure sensor [https://www.rockauto.com/catalog/moreinfo.php?pk=2313108&cc=1443428&jnid=516&jpid=0](https://www.rockauto.com/catalog/moreinfo.php?pk=2313108&cc=1443428&jnid=516&jpid=0) is located on top of the fuel tank.

In order to replace it, the fuel tank needs to be dropped from under the vehicle.

Tester

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**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\
**Post date:** [December 16, 2015, 9:28am UTC](https://community.cartalk.com/t/09-focus-se-code-p0451/91969/5 "2015-12-16T09:28:57Z")

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Evap system problems are a common complaint here, and can be difficult to diagnose.  
Info below might help for understanding the proper diagnosis procedure

[http://www.agcoauto.com/content/news/p2\_articleid/294](http://www.agcoauto.com/content/news/p2_articleid/294)  
[http://www.agcoauto.com/content/news/p2\_articleid/295](http://www.agcoauto.com/content/news/p2_articleid/295)