How To Fix ME159 - Function modules invoked in wrong sequence

SAP Error Message - Details

• Message type: E = Error

• Message class: ME - Purchasing: General Messages

• Message number: 159

• Message text: Function modules invoked in wrong sequence

What causes this issue?

The function modules for fully-automatic PO generation have been
invoked in the wrong sequence. The correct sequence is as follows:
1. ME_REFRESH_PO once
2. ME_CREATE_PO_HEADER once
3. ME_CREATE_PO_ITEM n times
4. ME_POST_PO once
If this sequence is not adhered to, data inconsistencies may arise.

How to fix this error?

Please ensure that the function modules are invoked as shown above.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message ME159 - Function modules invoked in wrong sequence ?

  The SAP error message ME159, which states "Function modules invoked in wrong sequence," typically occurs in the context of purchasing documents, such as purchase orders or purchase requisitions. This error indicates that the sequence of function module calls in a program or transaction is not being followed correctly, which can lead to inconsistencies or unexpected behavior in the application.
  Causes:
  
  Incorrect Function Module Sequence: The error often arises when a function module that is expected to be called before another is not executed in the correct order. This can happen due to custom code or enhancements that modify the standard flow.
  Missing Data: If certain prerequisite data is not available or has not been initialized before calling a function module, it can lead to this error.
  Custom Development: If there are custom developments or modifications in the purchasing process, they may not adhere to the expected sequence of function calls.
  User Exits or BAdIs: If user exits or Business Add-Ins (BAdIs) are implemented incorrectly, they may disrupt the normal flow of function calls.
  
  Solutions:
  
  Check Function Module Documentation: Review the documentation for the function modules being used to ensure they are being called in the correct order.
  Debugging: Use the SAP debugger to trace the sequence of function calls leading up to the error. This can help identify where the sequence is broken.
  Review Custom Code: If there is custom code involved, review it to ensure that it adheres to the expected sequence of function calls. Look for any modifications that may have been made to standard SAP processes.
  Consult SAP Notes: Check the SAP Support Portal for any relevant SAP Notes that may address this specific error or provide guidance on the correct sequence of function calls.
  Testing: After making changes, thoroughly test the purchasing process to ensure that the error is resolved and that no new issues have been introduced.
  
  Related Information:
  
  Function Modules: Familiarize yourself with the specific function modules involved in the purchasing process, such as ME_CREATE_DOCUMENT, ME_UPDATE_DOCUMENT, etc.
  SAP Documentation: Refer to SAP Help documentation for purchasing processes to understand the expected flow and dependencies.
  SAP Community: Engage with the SAP Community forums to see if others have encountered similar issues and what solutions they have found.
  Transaction Codes: Be aware of transaction codes related to purchasing, such as ME21N (Create Purchase Order), ME22N (Change Purchase Order), and ME23N (Display Purchase Order), as they may provide context for the error.
  
  By following these steps, you should be able to identify the cause of the ME159 error and implement a solution to resolve it.