  We present the one-loop electroweak renormalization of the CP violating
2-Higgs-Doublet Model with softly broken $\mathbb{Z}_2$ symmetry (C2HDM). The
existence of CP violation in the scalar sector of the model leads to a quite
unique process of renormalization, since it requires the introduction of
several non-physical parameters. The C2HDM will thus have more independent
counterterms than independent renormalized parameters. As a consequence,
different combinations of counterterms can be taken as independent for the same
set of independent renormalized parameters. We compare the behaviour of
selected combinations in specific NLO processes, which are assured to be gauge
independent via a simple prescription. FeynMaster 2 is used to derive the
Feynman rules, counterterms and one-loop processes in a simultaneously
automatic and flexible way. This illustrates its use as an ideal tool to
renormalize models such as the C2HDM and investigate them at NLO.
