Autonomous driving (AD) system designers need methods to efficiently debug vulnerabilities found in control algorithms. Existing methods lack alignment to the requirements of AD control designers to provide an analysis of the parameters of the AD system and how they are affected by cyber-attacks. We introduce ADAssure, a methodology for debugging AD control system algorithms that incorporates automated mechanisms which support generation of assertions to guide the AD system designer to identify vulnerabilities in the system. Our evaluation of ADAssure on a real-world AD vehicular system using diverse cyber-attacks developed a set of assertions that identified weaknesses in the OpenPlanner 2.5 AD planning algorithm and its constituent planning functions. Working with an AD control system designer and safety validation engineer, the results of ADAssure identified remediation of the AD control system, which can support the implementation of a redundant observer for data integrity checking and improvements to the planning algorithm. The adoption of ADAssure improves autonomous system design by providing a systematic approach to enhance safety and reliability through the identification and mitigation of vulnerabilities from corner cases.