Sordo, who replaces the injured Jari-Matti Latvala in the Ford World Rally Team, completed a full day of testing at M-Sport's Greystoke facility in Cumbria today - not tomorrow as previously reported.
The Spaniard is expected to continue running in the car until the early evening, gaining as much experience of the Fiesta as possible ahead of the fifth round of the WRC.
Sordo said: "I am really excited about going to Argentina. When you are a rally driver all you want to do is to compete, so I am really happy that Prodrive has given me the chance to drive the Ford."
The Spaniard will remain at M-Sport's Cumbrian base tomorrow, working with the engineers in an effort to familiarise himself with the Fiesta ahead of his one-off Rally Argentina drive.