As Roger noted, Fords seem have this function in them.
The '05 ST appears to have similar style odometer as the '02 Stang I used to have. I've never tried it on my ST because I have the analog/roller type odometer. Here's how I got it to work on the Stang. It may work on the Gen 1 ST's with digital odometer display.
Activating Test Mode
To enter the HEC Dealer test mode, depress and hold the instrument cluster SELECT/RESET button, turn the ignition switch to the RUN position, and then continue pressing the SELECT/RESET button (5 seconds) until tESt is displayed in the odometer. The SELECT/RESET button must be released within 3 seconds of the odometer tESt display to begin the dealer test mode.
Depress the SELECT/RESET button to advance through the following steps until dtc is displayed. Depressing the SELECT/RESET button will display any stored continuous DTCs before proceeding to the next step.