A modification of the bi-directional iterative soft-output Viterbi algorithm (Bi-SOVA) for decoding of turbo product codes is proposed. It was shown that the modification reduces the number of mathematical operations of comparison. An assessment of modification effectiveness is done. It is conducted the simulation of data channel of turbo codes with different parameters work which showed that the loss of energy efficiency of the decoding algorithm is compared with the modification to the algorithm without modification is not detected. These results allow to recommend the use of modified algorithm in the receiving equipment to reduce the computational complexity of the device and, therefore, reduce the cost of the final product. Further study may be devoted to the modeling of other channels of communication with other parameters of turbo product codes and assessing the modification effectiveness of bi-directional iterative soft-output Viterbi algorithm (Bi-SOVA) for decoding the codes of product.