Thin film solar cells based on Cu2ZnSnS4 (CZTS) absorber material suffers from performance issues arising due to the presence of a non-optimal back contact barrier, low carrier lifetime, acceptor/donor point defects in bulk, interface defects at the absorber-buffer junction and grain boundaries within the absorber. We perform comprehensive simulations enumerating the impact of these performance limiting factors on CZTS solar cells. These simulations capture the experimentally observed anomalies in current-voltage (I-V) characteristics and the open-circuit voltage (V-OC) pinning in CZTS solar cells. These cause-effect relationships as elaborated in the findings are expected to be of great interest to the experimentalists working in this field.