The eastern segment of SR 54 runs concurrently with SR 94 from Jamacha Boulevard east through the unincorporated, but commercially developed, area of Rancho San Diego, and follows Campo Road about east. Passing near Cuyamaca College, SR 54 and CR S17 continue northeast on six-lane Jamacha Road to El Cajon, while Campo Road and SR 94 split off to the southeast. East of Brabham Street, four-lane SR 54 continues through suburban development to where it currently ends at the El Cajon city limit, though Jamacha Road extends into the city to the route's previous terminus at the intersection with I-8.