Method for checking a signal transmission of a specified message with a number of d bits from a sender to a receiver by a control unit using a linear block code, which code is created using a coding tool, a channel model, and a linear feedback shift register, with the following steps: - description of the channel model by a characterising Markov-modulated Bernoulli process, - iterative first calculation of probability values for a probability distribution of states of one of the d bits relative to a current bit after signal transmission by a signal transmission unit, starting from the current probability distribution of the states in the current bit, taking into account all the possible transitions that result from the Cartesian product of the number of states according to the specified Markov-modulated Bernoulli process and the number of states of the linear feedback shift register, wherein the control unit adds the probability values of transitions into an equal state and carries out this iteration up to the probability distribution of the final bit, - iterative second calculation of probability values for the probability distribution of the states of one of the d bits relative to a current bit after signal transmission by the signal transmission unit, starting from the current probability distribution of the states in the current bit, ignoring all the transitions out of a specified zero state, wherein the control unit adds the probability values of transitions into an equal state and carries out this iteration up to the probability distribution of the final bit, - forming a difference from the probability values of the specified zero state out of the first iterative calculation with the probability values of the specified zero state out of the second iterative calculation, as a residual error probability. - description of the channel model by a characterising Markov-modulated Bernoulli process, - iterative first calculation of probability values for a probability distribution of states of one of the d bits relative to a current bit after signal transmission by a signal transmission unit, starting from the current probability distribution of the states in the current bit, taking into account all the possible transitions that result from the Cartesian product of the number of states according to the specified Markov-modulated Bernoulli process and the number of states of the linear feedback shift register, wherein the control unit adds the probability values of transitions into an equal state and carries out this iteration up to the probability distribution of the final bit, - iterative second calculation of probability values for the probability distribution of the states of one of the d bits relative to a current bit after signal transmission by the signal transmission unit, starting from the current probability distribution of the states in the current bit, ignoring all the transitions out of a specified zero state, wherein the control unit adds the probability values of transitions into an equal state and carries out this iteration up to the probability distribution of the final bit, - forming a difference from the probability values of the specified zero state out of the first iterative calculation with the probability values of the specified zero state out of the second iterative calculation, as a residual error probability.