This paper explains the concept of “modulo weight-based codes” and presents an efficient scheme for concurrent error detection of arbitrary multilevel circuits based on these codes. It is shown that in most cases modulo weight-based codes can achieve high fault detection capabilities of around 99% with just three check bits and without constraining the circuit structure. Modulo weight-based codes, present a way of exploiting the circuit structure to increase fault detection capability. An optimum choice of weights for the code can be made using information about the circuit structure. The paper presents an efficient algorithm to achieve the weight assignment based on simple estimates of the probabilities of the existence of sensitized paths from the signal line to the circuit outputs. Finally, a self-checking checker design is presented for the proposed modulo weight-based codes.