# Engine light is on

**URL:** <https://community.cartalk.com/t/engine-light-is-on/36225>\
**Category:** Maintenance/Repairs\
**Tags:** outback, subaru\
**Created:** [September 6, 2009, 6:07pm UTC](https://community.cartalk.com/t/engine-light-is-on/36225 "2009-09-06T18:07:16Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![orrwmwm](https://avatars.discourse-cdn.com/v4/letter/o/dc4da7/32.png) [@orrwmwm](https://community.cartalk.com/u/orrwmwm)\
**Post date:** [September 6, 2009, 6:07pm UTC](https://community.cartalk.com/t/engine-light-is-on/36225/1 "2009-09-06T18:07:16Z")

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I have a 1998 outback, the engine light is on, I have taken it to the shop, the computer show code 00400 an EGR valve problem, I have changed it out and the problem still exist and my machanic is stumped, and ideas? not effecting the proformance.

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**Author:** ![cigroller](https://avatars.discourse-cdn.com/v4/letter/c/c68b51/32.png) [@cigroller](https://community.cartalk.com/u/cigroller)\
**Post date:** [September 6, 2009, 9:16pm UTC](https://community.cartalk.com/t/engine-light-is-on/36225/2 "2009-09-06T21:16:18Z")

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Was anything actually checked or tested before just changing out the valve? The code doesn’t say that the valve is bad - only that there wasn’t enough exhaust going into the cylinder. This can happen for several different reasons.

Check this out to move forward: [http://www.obd-codes.com/p0400](http://www.obd-codes.com/p0400)