in my 2006 impreza my check engine light came on the other day and the tester i have didn't work. it was for obd2 and can what kind of tester should work. i took it into autozone and there tester couldn't figure it out either it just said something about routine mainenance needed,does that mean tune up and oil change or is it something more sinister?

Have the code pulled again. You should get a much better description of the problem. Ask for the code read number. Post it here, if the description given to you is not any better.

 

Codes don't advise routine maintenance like tune up and oil changes. Most codes are advising problems with pollution control. 

I'm not sure about Subaru's but some other cars have a "Service Engine Soon" light which is commonly mistaken for a check engine light. The service engine soon light is typically the light for oil changes etc...