  The hypernuclei $^4_\Lambda$He and $^4_\Lambda$H provide important
information on the hyperon-nucleon interaction. We present accurate
Faddeev-Yakubovsky calculations for the $\Lambda$ separation energies of the
$0^+$ ground and the $1^+$ excited states based on the Nijmegen SC YN
interactions. We explicitly take the $\Sigma$ admixture into account. Mass
differences of the baryons and the charge-dependence of the interaction are
considered. The results show that the Nijmegen models cannot predict all
separation energies simultaneously hinting to failures of the current
interaction models.
