The '49ers Code was a code used by miners, most famously during the Gold Rush, that contained a hidden meaning.
Dante Foxx first introduces the code to Jake Taylor at the Kids' Favorites Awards when they snuck away from the superficial starlets. Jake recalls all the Western stories Sophie Metcalf knows, and mentions her to Dante, who thinks about interviewing her. This leads to Jake to realize that he enjoys Sophie's company more than celebrities'.
Once Deputy Grady holds Jake prisoner, Jake sends a text using the '49ers Code to Sophie, which once deciphered, reveals where he is. Sophie unravels its meaning which allows her to rescue him.