This fault tree analysis diagram identifies the primary causes contributing to an ACC (Adaptive Cruise Control) system failure, depicted at the top of the diagram. The main event, ‘ACC Failure’, is analyzed through an OR gate, which indicates that any of the following failures would result in the top event: software failure, hardware failure, or communication failure. These branches are further detailed with specific error codes (B-014, B-015, B-016), helping in the diagnostic process to pinpoint the exact nature of the problem within complex systems.