A processor-implemented method, according to one embodiment, includes: activating a subset of a plurality of p-MTJ cells oriented in one or more columns of a MRAM array. Activating the subset of p-MTJ cells includes: applying a first voltage to a gate terminal of the transistor in each of the p-MTJ cells in parallel, applying a second voltage to a first end of the MTJ sensor in each of the p-MTJ cells in parallel, and applying a third voltage to a drain terminal of the transistor in each of the p-MTJ cells in parallel. The processor-implemented method also includes: monitoring the activated subset of p-MTJ cells, determining whether any of the activated p-MTJ cells have failed, and in response to determining that an activated p-MTJ cell has failed, physically locating the failed p-MTJ cell. Other systems, methods, and computer program products are described in additional embodiments.