How To Fix MN161 - Calculation rule &1 not defined (function module &2)

SAP Error Message - Details

• Message type: E = Error

• Message class: MN - Message class for subsequent settlement (Purchasing)

• Message number: 161

• Message text: Calculation rule &1 not defined (function module &2)

What causes this issue?

An evaluation of condition records with calculation rule &V1& is not
possible.
The program called for evaluation cannot process calculation rule &V1&.

System Response

The condition record is not evaluated.

How to fix this error?

Contact your system administrator, as an internal error has occurred.
The error occurred in function module &V2&.
Either this was called with incorrect data or evaluation of condition
records using calculation rule &V1& is not programmed.
The condition record concerned has (internal) number &V3&, and
condition item number &V4&.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message MN161 - Calculation rule &1 not defined (function module &2) ?

  The SAP error message MN161, which states "Calculation rule &1 not defined (function module &2)," typically occurs in the context of the SAP system when there is an issue with the configuration of calculation rules in the system. This error is often related to the use of function modules that are expected to perform certain calculations but cannot find the necessary configuration or definitions.
  Cause:
  
  Missing Configuration: The calculation rule specified by &1 is not defined in the system. This could be due to a missing entry in the configuration tables.
  Incorrect Function Module: The function module specified by &2 may not be correctly implemented or may not exist in the system.
  Transport Issues: If the configuration was recently transported from another system, it may not have been transported correctly, leading to missing definitions.
  Custom Development: If there are custom developments involved, the custom function module may not be properly defined or activated.
  
  Solution:
  
  
  Check Configuration:
  
  Go to the relevant configuration transaction (e.g., SPRO) and navigate to the area where calculation rules are defined.
  Ensure that the calculation rule specified in the error message is correctly defined and active.
  
  
  
  Verify Function Module:
  
  Use transaction SE37 to check if the function module specified in the error message exists and is active.
  If it is a custom function module, ensure that it has been properly implemented and activated.
  
  
  
  Transport Requests:
  
  If the issue arose after a transport, check the transport logs to ensure that all necessary objects were included and transported correctly.
  If needed, re-transport the configuration or manually create the missing entries.
  
  
  
  Consult Documentation:
  
  Review SAP documentation or notes related to the specific calculation rule and function module to ensure that all prerequisites are met.
  
  
  
  Debugging:
  
  If you have access to debugging tools, you can set breakpoints in the function module to see where the error occurs and gather more information about the context.
  
  
  
  Contact SAP Support:
  
  If the issue persists and you cannot find a resolution, consider reaching out to SAP support for assistance, especially if it involves standard SAP functionality.
  
  
  
  Related Information:
  
  Transaction Codes: Familiarize yourself with relevant transaction codes such as SPRO (Customizing), SE37 (Function Module), and SE80 (Object Navigator).
  SAP Notes: Search for SAP Notes related to error MN161 for any specific patches or updates that may address the issue.
  Documentation: Review the SAP Help Portal for documentation on calculation rules and function modules relevant to your specific SAP module (e.g., MM, SD, etc.).
  
  By following these steps, you should be able to identify and resolve the cause of the MN161 error in your SAP system.