  The IceCube neutrino observatory is a 3D array of photodetectors installed in
the Antarctic ice. It consists of 5,160 photomultiplier-tubes spread among 86
vertical strings making a total detector volume of more than a cubic kilometer.
It detects neutrinos via Cherenkov light of charged relativistic particles from
neutrino interactions with the detector volume. IceCube is, due to its size and
photosensor spacing, particularly sensitive to high-energy neutrinos. In this
analysis we search for dark matter that annihilates into a metastable mediator
that subsequently decays into Standard Model particles. These models yield an
enhanced high-energy neutrino flux from dark matter annihilation inside the Sun
compared to models without a mediator. Neutrino signals that are produced
directly inside the Sun are strongly attenuated at higher energies due to
interactions with the solar plasma. In the models considered here, the mediator
can escape the Sun before producing any neutrinos, thereby avoiding
attenuation. IceCube is ideal to search for this enhanced high-energy neutrino
signal. We present the sensitivities of an analysis of six years of IceCube
data looking for dark matter in the Sun considering mediator lifetimes between
1 ms to 10 s and dark matter masses between 200 GeV and 10 TeV. We show that
IceCube is sensitive to spin--dependent cross--sections of $3.45 \times
10^{-34}~\rm cm^2$ for dark matter masses of 1 TeV.
