The member of the solar system with an equatorial diameter of 3.48 x 10^3 kilometers is Pluto.

Here's why:

* Pluto's diameter is approximately 2,376.6 kilometers.

* 3.48 x 10^3 kilometers is equivalent to 3,480 kilometers.

While Pluto is no longer considered a planet, it is still a dwarf planet and a significant object in our solar system.