How do you reset the check engine light on a 2001 Subru Forester?

Disconnecting the battery erases all the accumulated information in the on-board computer. This will kill the light, but only temporarily. As soon as you start driving, the computer will start collection again, and if there is a problem the light will come up again. It won't happen immediately, may require driving about 100 miles, but it will come back. Be aware that if you kill the light this way and then go for an OBD inspection, the inspector's equipment will detect that your computer was reset recently (there are multiple readiness codes). You will be turned away and asked to come after sufficient driving. Chances are your light will be up after that. It makes sense to buy an OBD code reader to be able to get an idea why the light is on. I saw on the Web readers for about $40. Unfortunately, all those generic readers do not read all the proprietary codes, and almost every manufacturer has them. But for a few bucks... you can save on unnecessary repairs or check how you were screwed... You can also go to your local auto parts store. Auto Zone and others will read the code and reset it for you in the hope that you will buy parts to fix the problem. If you buy the $40 code reader, the ones I've seen don't have a reset feature. Spend $100 and you get the reset function. Haven't seen the proprietary codes that the reader won't read, but I do have a chart of Subaru codes that may be a little different from the ones in the manual that came with the reader.