A method for diagnosing of communication connections (31, 32) in a communication system, comprising the steps of: a) providing a plurality of diagnosing units and at least one further diagnosing unit, wherein the diagnosing units (21 - 28) are assigned to different communication connections (31, 32) of the communication system and are adapted to determine a value of at least one diagnosis variable of the respective assigned communication connections; b) determining a value of the at least one diagnosis variable by each of the plurality of diagnosing units; c) determining a value of the at least one diagnosis variable by the at least one further diagnosing unit; d) transferring the values determined by each of the diagnosing units to an evaluation unit (41, 42); e) statistically evaluating, by the evaluation unit (41, 42), the values as determined by the plurality of diagnosing units, wherein the statistical evaluation by the evaluation unit (41, 42) comprises determining an upper limit value and/or a lower limit value for the at least one diagnosis variable, wherein as an upper limit value for the at least one diagnosis variable a value is determined below which a predetermined proportion of the values of the respective diagnosis variable as determined by the plurality of diagnosing units lies, or wherein as a lower limit value for the at least one diagnosis variable a value is determined above which a predetermined proportion of the values of the respective diagnosis variable as determined by the plurality of diagnosing units lies, and wherein the predetermined proportion is less than 100 %; and f) diagnosing the values determined by the at least one further diagnosing unit based on the statistical evaluation by the evaluation unit (41, 42) for detecting predefined error types, wherein the diagnosing comprises comparing the values determined by the at least one further diagnosing unit with the upper and/or lower limit values, wherein steps b) to f) are repeated in predetermined time intervals and/or in case of a change of the configuration of the communication system. a) providing a plurality of diagnosing units and at least one further diagnosing unit, wherein the diagnosing units (21 - 28) are assigned to different communication connections (31, 32) of the communication system and are adapted to determine a value of at least one diagnosis variable of the respective assigned communication connections; b) determining a value of the at least one diagnosis variable by each of the plurality of diagnosing units; c) determining a value of the at least one diagnosis variable by the at least one further diagnosing unit; d) transferring the values determined by each of the diagnosing units to an evaluation unit (41, 42); e) statistically evaluating, by the evaluation unit (41, 42), the values as determined by the plurality of diagnosing units, wherein the statistical evaluation by the evaluation unit (41, 42) comprises determining an upper limit value and/or a lower limit value for the at least one diagnosis variable, wherein as an upper limit value for the at least one diagnosis variable a value is determined below which a predetermined proportion of the values of the respective diagnosis variable as determined by the plurality of diagnosing units lies, or wherein as a lower limit value for the at least one diagnosis variable a value is determined above which a predetermined proportion of the values of the respective diagnosis variable as determined by the plurality of diagnosing units lies, and wherein the predetermined proportion is less than 100 %; and f) diagnosing the values determined by the at least one further diagnosing unit based on the statistical evaluation by the evaluation unit (41, 42) for detecting predefined error types, wherein the diagnosing comprises comparing the values determined by the at least one further diagnosing unit with the upper and/or lower limit values, wherein steps b) to f) are repeated in predetermined time intervals and/or in case of a change of the configuration of the communication system.