Affordable and clean energy has been one of the major objectives adopted by United Nations under the 2030 Agenda for Sustainable Development. In this direction, fuel cell electric vehicles have gained popularity in recent times due their efficiency and environmental friendliness. Fundamentally, it uses compressed hydrogen from the vehicle-mounted tank and combines with ambient air to generate DC electricity. Water is created as a by-product and expelled through the tailpipe. The technology being integrated on powertrain architecture, along with battery pack can prove to be an efficacious approach for zero emission automotive system. However, hydrogen being the primary fuel, and being stored at high pressure, the system involves handling and potential hazards of hydrogen, and possibility of explosions due to hydrogen leaks. Hence, safety is the key issue in handling fuel cell vehicles. This paper discusses about role of Unified Diagnostic Services (UDS) in providing safety and precautionary aspects for the fuel cell vehicles. UDS has been first time developed for fuel cell vehicle, in India in accordance with fault codes by fuel cell stack, applied on TML FCEV bus. It discuss about how UDS can be used to anticipate key safety issues such as hydrogen leaks, pressure monitoring system, and analyzing the Diagnostic Troubleshooting Codes (DTC) from fuel cell stack. In order to improve the dependability, durability, and safety of fuel cell vehicles (FCVs), diagnostic services are essential since they assist in the real-time detection and identification of defects. Apart from identifying DTC codes from the stack, this paper also discuss about how the key UDS services like, diagnostic and communication management services, data transmission services, input output control services, etc. can be implemented for the fuel cell controller unit (FECU). As a part of novelty, the role of AUTOSAR modules such as DEM and DCM in handling the faults has also been discussed in brief.