As an open defect occurs in one wire segment of the circuit, different logic values on the coupling wires of the physical layout may result in different faulty behaviours, which are so called the Byzantine effect. Many previous researches focus on the test and diagnosis of open defects but the pattern diagnosability has not properly addressed. Therefore in this study, a high-resolution diagnostic framework for open defects is proposed and consists of a diagnostic test-pattern generation (DTPG) and its diagnosis flow. The branch-and-bound search associated with controllability analysis is incorporated in satisfiability-based DTPG to generate patterns for the target segment. Later, a precise diagnosis flow constructs the list of defect candidates in a dictionary-based fashion followed by an inject-and-evaluate analysis to greatly reduce the number of candidates for silicon inspection. Experimental results show that the proposed framework runs efficiently and deduces nearly one candidate for each open-segment defect on average among all ISCAS'85 benchmark circuits.