A method for operating a diagnostic system of a vehicle including a fail operational power system (FOPS) module and a fail operational system (FOS) module includes the FOS module requesting a microcontroller of the FOPS module to generate a diagnostic control signal. The FOS module receives the diagnostic information from a component module of the FOPS module based on the diagnostic control signal generated by the microcontroller. The FOS module executes isolator diagnostics based on the received diagnostic information.