An urgent task is to correct errors that occur during the transmission and storage of information. To solve this problem, various noise-resistant codes have recently been increasingly used. Turbo codes have the best correcting ability in data transmission channels with a high probability of an erroneous bit. To obtain the necessary characteristics, various combinations of codes and encoding and decoding methods are used. If another block of information bits is added to the codeword of a systematic block or systematic convolutional code, then it will be possible to implement decoding of such a codeword by a turbo code decoder. The disadvantage of the resulting combined code is its extremely low correcting ability in the presence of errors in the check bits of the codeword. The article shows that the correcting ability of the presented code can be significantly increased by multiplying the decoded values of the check bits by reduction factors.