We present and numerically demonstrate a polarization-division multiplexing 16-ary quadrature amplitude modulation faster-than-Nyquist (FTN-PDM-16QAM) system enabled by the Tomlinson-Harashima precoding (THP). The THP module is located before the polarization separation module and it is shown that the modulo operator of the THP module at the receiver needs to be removed in order to fully optimize the performance of the soft-decision forward error correction (FEC). The impact of various parameters such as the modulo size factor, the 3-dB bandwidth and roll-off factor of the Nyquist filter on the performance of the FTN-PDM-16QAM system are also investigated. In addition, we compare the FTN-PDM-16QAM system with the PDM-16QAM Nyquist system in terms of the system performance and implementation complexity.