Check Engine Light

I have 64,000 miles on my 3.4L V6 Tacoma Prerunner and my check engine light came on. I tried to reset it by disconnecting the battery but no luck. It stays on permanently now. I was thinking about purchasing the Equus 3100 OBII Scan Tool, but I am not too sure cause I have heard that it might deploy your airbags and that erases all your memory completely when clearing the codes with it. Does anyone have any idea what I should do? I am trying to not go to the dealer if at all possible. Thanks in advance.