As you then can check, see and do to resolve the problem situation(SC not connecting to PAM properly with SC-test button):
1. Disk drive C: got filled
2. First we deleted from %USM_HOME%\logs several large .hprof files
3. Then after a SC-service restart, C-drive got filled rapidly there after
4. As it appeared, %USM_HOME%\logs\jms-data folder contained about 120GB of tx_nnnn.tmp files
5. We removed those
6. And we removed the jms-data\db.redo and db.data files then too
7. Next step is to restart SC-service
>> Note: Because of the rebuild, it may take longer for Service Catalog to completely startup.
8. SC/admin/config/PAM>Test now processed successfully.
9. And SC-requests got their PAM=process started (although slow)
10 The slowness (for both SC and PAM) might be caused by the 'huge startup' situation now.
11 Give the system the time to get in balance.