To display trouble codes on a Ford vehicle, you will need the a code scanner, and as of 2010, not one code scanner fits all trouble codes. Fords made after 1996 operate under On-Board Diagnostic (OBD-II) coding, but the brakes, tire pressure monitoring and the other diagnostic systems cannot be read by and OBD-II reader. Those systems require their own dedicated code reading hardware. Yet, all diagnostic systems can be accessed the same way. Every Ford manufactured after 1996 has a data link connection beneath the dashboard, usually somewhere near the underside of the steering wheel.
Open the Ford's driver's side door, and place the key in the ignition. Do not turn the electrical system on yet. Just leave the key there, for later use.
Connect the diagnostic to the data link connection.
Turn the key in the ignition so that the electrical system comes on. If your particular code reader has an "auto on" function, it will come to life as soon as it senses incoming data. If your scanner does not have this feature, you will have to turn the scanner on.
Wait a few seconds. As soon as the scanner connects with the diagnostic system, the trouble code will be displayed on the scanner's screen.
