# P0420 - 2002 Toyota Camry

**URL:** <https://community.cartalk.com/t/p0420-2002-toyota-camry/157872>\
**Category:** Maintenance/Repairs\
**Tags:** toyota, camry\
**Created:** [February 3, 2020, 11:55pm UTC](https://community.cartalk.com/t/p0420-2002-toyota-camry/157872 "2020-02-03T23:55:20Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![dolores23rollinger\_162923](https://avatars.discourse-cdn.com/v4/letter/d/bc79bd/32.png) [@dolores23rollinger\_162923](https://community.cartalk.com/u/dolores23rollinger_162923)\
**Post date:** [February 3, 2020, 11:55pm UTC](https://community.cartalk.com/t/p0420-2002-toyota-camry/157872/1 "2020-02-03T23:55:21Z")

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P0420 code “Catalyst System Efficiency Below Threshold (Bank 1).

Changed 02 upstream sensor  
Reset code by disconnecting battery 1 hr

Check engine light has been going on and off since not blinking. But in for ahile then off. Usually comes on while driving then off next time I start it then back on as driving.

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**Author:** ![TXdealer](https://avatars.discourse-cdn.com/v4/letter/t/50afbb/32.png) [@TXdealer](https://community.cartalk.com/u/TXdealer)\
**Post date:** [February 4, 2020, 2:39pm UTC](https://community.cartalk.com/t/p0420-2002-toyota-camry/157872/2 "2020-02-04T14:39:32Z")

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You probably need a new catalytic converter, but a shop can determine for sure. Not super expensive unless you live in California and have to buy a OEM spec part.

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**Author:** ![Honda-Blackbird](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/honda-blackbird/32/3159_2.png) [@Honda-Blackbird](https://community.cartalk.com/u/Honda-Blackbird)\
**Post date:** [February 4, 2020, 2:42pm UTC](https://community.cartalk.com/t/p0420-2002-toyota-camry/157872/3 "2020-02-04T14:42:28Z")

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Does this vehicle have ANY exhaust leaks? You cannot have any leaks in the system.

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**Author:** ![dolores23rollinger\_162923](https://avatars.discourse-cdn.com/v4/letter/d/bc79bd/32.png) [@dolores23rollinger\_162923](https://community.cartalk.com/u/dolores23rollinger_162923)\
**Post date:** [February 4, 2020, 7:55pm UTC](https://community.cartalk.com/t/p0420-2002-toyota-camry/157872/4 "2020-02-04T19:55:49Z")

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None that. I have noticed, I will definitely have to check thoroughly

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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:** [February 5, 2020, 12:16am UTC](https://community.cartalk.com/t/p0420-2002-toyota-camry/157872/5 "2020-02-05T00:16:23Z")

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The same code came up on my old 02 Camry. I replaced both o2 sensors and never had another problem. Gave the car away 75k miles later still no code.

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**Author:** ![Honda-Blackbird](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/honda-blackbird/32/3159_2.png) [@Honda-Blackbird](https://community.cartalk.com/u/Honda-Blackbird)\
**Post date:** [February 5, 2020, 1:03am UTC](https://community.cartalk.com/t/p0420-2002-toyota-camry/157872/6 "2020-02-05T01:03:57Z")

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Replacing one of the two O2 sensors isn’t the way to go… the two sensors basically compare notes, so one can throw off the other.

I’d try what @PvtPublic did and see whatchagets