Every so often the check engine light will come on in a Ford Mustang. While this light is an indicator that there are problems with the car, much of the time it's more of an reminder to have the car serviced. These lights are programmed at various intervals to come on for that purpose. Not everyone takes his car to a dealer for servicing, however, and there is a way of turning it off.
Move the driver's seat to the far rear position to give yourself more room to work.
Look under the dash near the center and find the covering that needs to be removed to access the panel for the OBD II connection. It is connected to the right side of the passenger compartment behind the center console where your radio is located.
Plug the OBD II plug into the connection on the car, following the manufacturer's instructions.
Turn the ignition on but do not start the car. Turn it far enough to provide power to everything.
Press the scan button on the scanner tool. This will tell you if there is anything wrong with the car. It will "throw" a code that you can look up in the booklet provided with the tool.
Choose yes when the tool asks you if you want to clear codes. This will clear all codes and reset the check engine light.
Turn the key off, unplug the OBD II Tester and replace the panel you removed to access the panel.
