A number of techniques determine defects in non-volatile memory arrays, which are particularly applicable to 3D NAND memory, such as BiCS type. Word line to word line shorts within a memory block are determined by application of an AC stress mode, followed by a defect detection operation. An inter-block stress and detection operation can be used to determine word line to word line leaks between different blocks. Select gate leak line leakage, for both the word lines and other select lines, is considered, as are shorts from word lines and select lines to local source lines. In addition to word line and select line defects, techniques determine shorts between bit lines and low voltage circuitry, such as in sense amplifiers.