What does AC02 mean in ISO 20022?

AC02 is Invalid Debtor Account Number in the ExternalReturnReason1Code code set: Debtor account number invalid or missing.

What should I do when I get AC02?

Check the debtor account in DbtrAcct against the customer's account master data. For a direct debit, ask the creditor to confirm the mandate holds the right account.

Where does AC02 appear in a message?

For example in pacs.004, element TxInf/RtrRsnInf/Rsn/Cd.

ExternalReturnReason1Code

AC02 Reason Code: Invalid Debtor Account Number

Written and maintained by ZagTrader. Last reviewed 21 October 2026. How this page is sourced and checked

AC02 means invalid debtor account number in the ISO 20022 return reason code set. The debtor account in the payment is missing or not valid at the bank that has to debit it.

Code: AC02
ISO name: InvalidDebtorAccountNumber
Status: Registered
Last updated: 2021-08-31

Official definition

Debtor account number invalid or missing.

Definition from the ISO 20022 External Code Sets, 2Q2026 (published 28 Aug 2026).

What it means in practice

In a pacs.004 payment return, a return reason code explains why funds that were already settled are being sent back. It sits in TxInf/RtrRsnInf/Rsn/Cd, and bank statements (camt.053, camt.054) repeat it in RtrInf/Rsn/Cd.

The debtor account in the payment is missing or not valid at the bank that has to debit it. You see it mostly in direct debits and in payment initiation (pain.001) where the ordering account is wrong.

What to do

Check the debtor account in DbtrAcct against the customer's account master data.
For a direct debit, ask the creditor to confirm the mandate holds the right account.

Messages and fields that use ExternalReturnReason1Code

Message	Element path
pacs.004	TxInf/RtrRsnInf/Rsn/Cd, OrgnlGrpInf/RtrRsnInf/Rsn/Cd
camt.053	Stmt/Ntry/NtryDtls/TxDtls/RtrInf/Rsn/Cd
camt.054	Ntfctn/Ntry/NtryDtls/TxDtls/RtrInf/Rsn/Cd
camt.052	Rpt/Ntry/NtryDtls/TxDtls/RtrInf/Rsn/Cd
trck.001	TrckrStsAndTx/Tx/RjctRtrRsn/Rsn/Cd, TrckrStsAndTx/TxSts/RjctRtrRsn/Rsn/Cd
trck.002	TrckrStsAndTx/Tx/RjctRtrRsn/Rsn/Cd, TrckrStsAndTx/TxSts/RjctRtrRsn/Rsn/Cd
trck.004	TrckrStsAndTx/Tx/RjctRtrRsn/Rsn/Cd, TrckrStsAndTx/TxSts/RjctRtrRsn/Rsn/Cd

AC02 in other code sets

AC02 questions

What does AC02 mean in ISO 20022?: AC02 is Invalid Debtor Account Number in the ExternalReturnReason1Code code set: Debtor account number invalid or missing.
What should I do when I get AC02?: Check the debtor account in DbtrAcct against the customer's account master data. For a direct debit, ask the creditor to confirm the mandate holds the right account.
Where does AC02 appear in a message?: For example in pacs.004, element TxInf/RtrRsnInf/Rsn/Cd.

All ExternalReturnReason1Code codes · ISO 20022 code sets

The ISO 20022 code names and definitions on this page are reproduced from material published at iso20022.org under the ISO 20022 Intellectual Property Rights policy. This is not the official source: the up-to-date ISO 20022 standards and repository material are published only at iso20022.org. Explanations in our own words are by ZagTrader. ZagTrader is not affiliated with or endorsed by ISO or Swift.