Turret with Siemens PLC 700024 Alarm, Help Needed!

Hi, Can anyone tell me how to track down a PLC alarm 700024 on a 802C controller? The alarm reads, TOOL NOT FOUND, MONITORING TIME UP. I am trying to fix the issue but the manuals do not specify exactly what's missing or causing it. This alarm comes up when I try to index the 6 position lathe tool turret. You hear the turret unlock but it refuses to index. The turret worked just fine before I did a factory reboot of the controller. Everything else appears to work fine. Thanks!