diff --git a/src/fsfw/pus/Service11TelecommandScheduling.tpp b/src/fsfw/pus/Service11TelecommandScheduling.tpp
index 3e48be0c..47135155 100644
--- a/src/fsfw/pus/Service11TelecommandScheduling.tpp
+++ b/src/fsfw/pus/Service11TelecommandScheduling.tpp
@@ -581,10 +581,12 @@ inline ReturnValue_t Service11TelecommandScheduling<MAX_NUM_TCS>::getMapFilterFr
   }
 
   // additional security check, this should never be true
-  if (itBegin->first > itEnd->first) {
+  if ((itBegin != telecommandMap.end() and itEnd != telecommandMap.end()) and
+      (itBegin->first > itEnd->first)) {
 #if FSFW_CPP_OSTREAM_ENABLED == 1
+    sif::error << "11::getMapFilterFromData: itBegin > itEnd\n" << std::endl;
 #else
-    sif::printError("11::GetMapFilterFromData: itBegin > itEnd\n");
+    sif::printError("11::getMapFilterFromData: itBegin > itEnd\n");
 #endif
     return returnvalue::FAILED;
   }