Just an FYI, disconnecting the battery on some OBD II cars won't reset the light. On others, it will but you have to cut the lights on too while the battery is disconnected. Another thing about OBD II cars is that even if you fix the problem, if you never reset the light it's gonna stay on, regardless of repairs. Some cars will still run the same afterwards. Best thing to do is to find someone who can read OBD II generic with CAN (centralized area Networking?) and find out what the code is.