Abstract: This disclosure describes systems, methods, and devices related to diagnose a broken scan chain and isolate the broken cell. A device may perform a functional test on a plurality of central processing unit (CPU) cells in a chain. The device may propagate data through a combinatoric logic. The device may capture results in sequential flip-flops associated with scan. The device may utilize the results in a next combinatoric logic. The device may utilize shifted-out data to isolate a first broken cell based on the functional test.