Diagnosis
In order to group characteristic values, the characteristic in questionhas to meet the following prerequisites:
The data type has to have format character format.
The maximum number of places is 18.
Function module WRF_CHECK_CHAR_VAL has to be specified in the ValueCheck via Function Module group frame in the Values tab page.

Procedure
Check the settings in characteristics management (transaction CT04).Then call the characteristic value group function again.