Battery Management Systems (BMSs) are safety-critical components in electric vehicles, demanding thorough testing under realistic and fault-prone conditions. This thesis presents the design and implementation of a high-performance battery monitor Integrated Circuit (IC) simulator for Hardware-In-the-Loop (HIL) applications. Designed for the NXP S32K344-based RD-K344BMU development board, the simulator emulates the MC33772 and MC33774 devices by accurately replicating their TPL2 and TPL3 communication protocols and internal register architectures. A key focus is placed on fault injection, a crucial requirement in validating BMS robustness in compliance with ISO 26262 standards. The simulator features dynamic runtime fault injection mechanisms, enabling the host system to introduce Cyclic Redundancy Check (CRC) errors, timing anomalies, register overrides, and communication faults.