Ferromagnetic (FM) systems have attracted interest because a variety of novel phases can arise near a quantum critical point (QCP) where the FM order is suppressed to zero temperature. The Kondo lattice compound CePtAl₄Si₂ is a candidate FM quantum critical material that becomes the FM state below T_c = 3.7 K, but the possibility of the quantum criticality has yet to be studied. Here, we report a comprehensive temperature-pressure phase diagram of CePtAl₄Si₂ using a systematic transport investigation. The FM compound CePtAl₄Si₂ goes through three distinct ground states under pressure. In the low-pressure FM state, T_c is gradually suppressed by pressure and a smooth extrapolation of T_c(P) reaches zero temperature at a critical pressure of 7.0 GPa. However, the suppression of T_c is interrupted by the appearance of another crossover temperature T^∗ in the intermediate pressure range of 5.4–11.7 GPa, which shows a nonmonotonic pressure dependence. A fully coherent Kondo screened state is observed in the high-pressure regime. These results suggest that a FM QCP is avoided under pressure in the disordered Kondo system CePtAl₄Si₂.