An automotive diagnostic machine is a hand-held tool that pulls and displays automotive diagnostic trouble codes, shows emissions related status and displays data that was set when the Check Engine light problem occurred. An automotive diagnostic machine is also called an OBD-II tool.
An automotive diagnostic machine gets this information by linking to a car's on-board diagnostic system through a port that is located either under the dash or under the hood of a car. An OBD-II tool is typically inexpensive, and some parts stores read codes for free. Vehicles manufactured in 1996 or later are equipped with the universal OBD-II codes.