# Check Engine Light/2000 Subaru Forrester

**URL:** <https://community.cartalk.com/t/check-engine-light-2000-subaru-forrester/10931>\
**Category:** Maintenance/Repairs\
**Created:** [February 20, 2008, 6:59pm UTC](https://community.cartalk.com/t/check-engine-light-2000-subaru-forrester/10931 "2008-02-20T18:59:39Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![donrico](https://avatars.discourse-cdn.com/v4/letter/d/b782af/32.png) [@donrico](https://community.cartalk.com/u/donrico)\
**Post date:** [February 20, 2008, 6:59pm UTC](https://community.cartalk.com/t/check-engine-light-2000-subaru-forrester/10931/1 "2008-02-20T18:59:39Z")

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Check engine light (CEL) first came on 8 months ago. Local mechanic reset the light and about every 500 to 700 miles CEL comes on again. Read-out from computer tool states, Catalytic Converter. Car has 86000 miles, oil changed every 3000 miles, get 30 mpg on highway. Had the light reset 5 days ago and went through inspection. Car passed and no problems. OK…why is the CEL coming on?

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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:** [February 20, 2008, 7:27pm UTC](https://community.cartalk.com/t/check-engine-light-2000-subaru-forrester/10931/2 "2008-02-20T19:27:22Z")

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Bad oxygen sensor?  
Bad catalytic converter?  
Bad mechanic?

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**Author:** ![NYBo](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nybo/32/17281_2.png) [@NYBo](https://community.cartalk.com/u/NYBo)\
**Post date:** [February 20, 2008, 7:42pm UTC](https://community.cartalk.com/t/check-engine-light-2000-subaru-forrester/10931/3 "2008-02-20T19:42:38Z")

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The exact code number would be helpful for us to assist you. I’ll bet it was something like P0420: Catalyst System Efficiency Below Threshold (Bank 1). Here’s a good explanation of the code:

> **[P0420 Catalyst System Efficiency Below Threshold](https://www.obd-codes.com/p0420)**
>
> How to diagnose, repair, and info on symptoms and causes of a P0420 engine code which means the catalytic converter is no longer performing at a normal level.

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**Author:** ![batman](https://avatars.discourse-cdn.com/v4/letter/b/9fc29f/32.png) [@batman](https://community.cartalk.com/u/batman)\
**Post date:** [February 20, 2008, 8:31pm UTC](https://community.cartalk.com/t/check-engine-light-2000-subaru-forrester/10931/4 "2008-02-20T20:31:37Z")

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you may just need a new fuel cap, or make sure it’s tight after filling up.

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**Author:** ![hoffmalr](https://avatars.discourse-cdn.com/v4/letter/h/bc8723/32.png) [@hoffmalr](https://community.cartalk.com/u/hoffmalr)\
**Post date:** [February 20, 2008, 8:36pm UTC](https://community.cartalk.com/t/check-engine-light-2000-subaru-forrester/10931/5 "2008-02-20T20:36:07Z")

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OK…why is the CEL coming on?

Because the car is telling you that something is wrong and needs to be checked.

Sorry, had to say it. Listen to VDC.