There are many reasons to want to turn off the "Check Engine" light on your Subaru Outback. You might already know what the problem is and are waiting to get it fixed. Or maybe you know there's not really a problem and your Outback is just being finicky. For whatever reason, the light can be annoying, and you want to turn it off.
Take your Subaru Outback to a dealer or car shop. The "Check Engine" light is designed to come on when service is needed. Each problem has a maintenance code, and a mechanic will be able to use this code to determine the nature of the problem. This is probably the safest way to go about things if you're unsure why the light turned on in the first place.
Check for simple reasons the light might be on. The light will come on, for example, if you didn't screw the gas cap on all the way the last time you filled your tank. Try unscrewing and replacing the gas cap carefully and then check for the light the next time you turn on your Outback.
Disconnect your battery for about half an hour. This should cause the light to stay off once you reconnect it. This does not, of course, fix the reason the light came on to begin with.
Turn your Subaru off and on a lot. It might take at least 20 times, but eventually the light will stop turning on. This is fairly tedious, but if you're determined to get it to turn off, it may be something you want to try.
There's probably a reason the light is on. If you're unsure about the cause, it's always safest to take your car to the shop to have it checked out. Just because you can get the light to turn off doesn't mean you've made the problem go away.