Functional safety is driven by number of standards like in automotive its driven by ISO26262, in Aerospace its driven by DO-178C, and in Medical its driven by IEC 60601. Automotive electronic controllers must adhere to state-of-the-art functional safety standard provided by ISO26262. A critical functional safety requirement is the Fault Handling Time Interval (FHTI), which includes the Fault Detection Time Interval (FDTI) and Fault Reaction Time Interval (FRTI). The requirements for FHTI are derived from Failure Mode Effect Analysis (FMEA) conducted at the system level. Various fault categories are analyzed, including electrical faults (e.g., short to battery, short to ground, open circuits), systemic faults (e.g., sensor value stuck, sensor value beyond range), and communication faults (e.g., incorrect CAN message signal values). Controllers employ strategies such as debouncing and fault time maturity to detect these faults. Numerous FDTI requirements must be verified to ensure compliance with FMEA-identified faults. Significant portion of total quantum of Test procedures of entire system are fault injection test cases, Manual testing of these cases is cumbersome, hence automating these tests is crucial for efficient regression testing. In HIL environment, ECU variables and communication signals are available for processing within tool which contains fault information which needs to be processed for FDTI calculations. The paper examines diverse strategies to handle the complexity of FDTI test cases in the HIL environment through automation, leveraging tool features, time trigger, time synchronization, post-processing techniques and real-time calculations during test execution to process FDTI calculations, ensuring thorough verification of functional safety requirements.