A method includes transmitting a first value to a first slave device via a communication bus, where the first value is within a first range of values associated with the first slave device. The method also includes receiving a second value via the communication bus and detecting a fault when the second value is not within the first range of values associated with the first slave device. Detecting the fault could include detecting a decoder fault when the second value is within a second range of values associated with a second slave device. The method may further include detecting a fault when the second value is within the first range of values associated with the first slave device but does not equal the first value or detecting no fault when the second value equals the first value.