A computer-implemented method for identifying errors in transaction messages associated with payment transactions. The method includes a step of receiving a transaction message associated with a financial transaction, whereby the financial transaction originates from a merchant and is processed by an acquirer. The transaction message comprises a plurality of data element fields, with at least one of the data element fields being a merchant identification field used to identify the merchant originating the financial transaction. An additional step includes performing an error-identification routine on the transaction message, with the error-identification routine including analyzing a merchant identification (ID) data element populated in the merchant identification field to determine if the merchant ID data element is not uniquely associated with the merchant. An additional step includes generating an error message indicating that the merchant ID data element is not uniquely associated with the merchant, and transmitting the error message to the acquirer.