A blood pump system for left ventricle assist comprising: an implantable pump unit having a multiphase brushless motor including windings for energizing according to first, second, and third phases; a subcutaneous cable having first, second, and third parallel pairs of redundant conductors, wherein the conductor pairs are connected to respective ends of the windings; and an external unit coupled to the cable, comprising: an H-bridge inverter having first, second, and third phase legs coupled to the first, second, and third conductor pairs, respectively; first and second pairs of power sensors responsive to electrical power in each of the redundant conductors in the first and second conductor pairs, respectively; and a controller coupled to the H-bridge inverter and the power sensors for 1) switching the H-bridge inverter in a sequence for operating the motor, 2) characterizing a first power utilization parameter of one of the conductor pairs during energization of the first phase, 3) characterizing a second power utilization parameter of one of the conductor pairs during energization of the second phase, 4) characterizing a third power utilization parameter of one of the conductor pairs during energization of the third phase, and 5) pairwise comparing the power utilization parameters and detecting a fault in the implantable pump in response to an imbalance of one of the comparisons. an implantable pump unit having a multiphase brushless motor including windings for energizing according to first, second, and third phases; a subcutaneous cable having first, second, and third parallel pairs of redundant conductors, wherein the conductor pairs are connected to respective ends of the windings; and an external unit coupled to the cable, comprising: an H-bridge inverter having first, second, and third phase legs coupled to the first, second, and third conductor pairs, respectively; first and second pairs of power sensors responsive to electrical power in each of the redundant conductors in the first and an H-bridge inverter having first, second, and third phase legs coupled to the first, second, and third conductor pairs, respectively; first and second pairs of power sensors responsive to electrical power in each of the redundant conductors in the first and second conductor pairs, respectively; and a controller coupled to the H-bridge inverter and the power sensors for 1) switching the H-bridge inverter in a sequence for operating the motor, 2) characterizing a first power utilization parameter of one of the conductor pairs during energization of the first phase, 3) characterizing a second power utilization parameter of one of the conductor pairs during energization of the second phase, 4) characterizing a third power utilization parameter of one of the conductor pairs during energization of the third phase, and 5) pairwise comparing the power utilization parameters and detecting a fault in the implantable pump in response to an imbalance of one of the comparisons. a controller coupled to the H-bridge inverter and the power sensors for 1) switching the H-bridge inverter in a sequence for operating the motor, 2) characterizing a first power utilization parameter of one of the conductor pairs during energization of the first phase, 3) characterizing a second power utilization parameter of one of the conductor pairs during energization of the second phase, 4) characterizing a third power utilization parameter of one of the conductor pairs during energization of the third phase, and 5) pairwise comparing the power utilization parameters and detecting a fault in the implantable pump in response to an imbalance of one of the comparisons.