# Code P0420: catalytic converter efficiency problem

**URL:** <https://community.cartalk.com/t/code-p0420-catalytic-converter-efficiency-problem/43298>\
**Category:** Maintenance/Repairs\
**Tags:** catalytic-converters, odyssey, honda\
**Created:** [January 27, 2010, 2:38am UTC](https://community.cartalk.com/t/code-p0420-catalytic-converter-efficiency-problem/43298 "2010-01-27T02:38:49Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![htsai1](https://avatars.discourse-cdn.com/v4/letter/h/73ab20/32.png) [@htsai1](https://community.cartalk.com/u/htsai1)\
**Post date:** [January 27, 2010, 2:38am UTC](https://community.cartalk.com/t/code-p0420-catalytic-converter-efficiency-problem/43298/1 "2010-01-27T02:38:49Z")

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My Honda Odyssey (year 2000 with 130,000 miles) check engine light came on. The code was P0420 which stated the catalytic converter efficiency issue. Is it necessary to replace the catalytic converter? Or, the problem can be solved by clean the oxygen sensor. Thanks.  
  
  
  
 Tsai

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**Author:** ![Caddyman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/caddyman/32/23_2.png) [@Caddyman](https://community.cartalk.com/u/Caddyman)\
**Post date:** [January 27, 2010, 2:42am UTC](https://community.cartalk.com/t/code-p0420-catalytic-converter-efficiency-problem/43298/2 "2010-01-27T02:42:21Z")

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It’s only an issue if you are facing an emissions test…If that is the case, I would replace BOTH O2 sensors first…They don’t last forever…

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**Author:** ![htsai1](https://avatars.discourse-cdn.com/v4/letter/h/73ab20/32.png) [@htsai1](https://community.cartalk.com/u/htsai1)\
**Post date:** [January 27, 2010, 2:51am UTC](https://community.cartalk.com/t/code-p0420-catalytic-converter-efficiency-problem/43298/3 "2010-01-27T02:51:19Z")

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A dealer was going to charge me $1500 for replacing the catalytic converter. Do you mean that I can try to replace the O2 sensors for now? How much does it cost to replace the oxygen sensors? Thanks.

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**Author:** ![hellokit](https://avatars.discourse-cdn.com/v4/letter/h/6a8cbe/32.png) [@hellokit](https://community.cartalk.com/u/hellokit)\
**Post date:** [January 27, 2010, 3:22am UTC](https://community.cartalk.com/t/code-p0420-catalytic-converter-efficiency-problem/43298/4 "2010-01-27T03:22:21Z")

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There is already a body of posts dealing with P0420. Learn more by clicking on Search, and puting Catalytic Converter in the keyword space.

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**Author:** ![htsai1](https://avatars.discourse-cdn.com/v4/letter/h/73ab20/32.png) [@htsai1](https://community.cartalk.com/u/htsai1)\
**Post date:** [January 27, 2010, 3:33am UTC](https://community.cartalk.com/t/code-p0420-catalytic-converter-efficiency-problem/43298/5 "2010-01-27T03:33:31Z")

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Thanks.