diff --git a/libraries/AP_Torqeedo/AP_Torqeedo.cpp b/libraries/AP_Torqeedo/AP_Torqeedo.cpp
index 0c92c7bd39..e03dec3ba0 100644
--- a/libraries/AP_Torqeedo/AP_Torqeedo.cpp
+++ b/libraries/AP_Torqeedo/AP_Torqeedo.cpp
@@ -208,6 +208,7 @@ bool AP_Torqeedo::healthy()
 }
 
 // run pre-arm check.  returns false on failure and fills in failure_msg
+// any failure_msg returned will not include a prefix
 bool AP_Torqeedo::pre_arm_checks(char *failure_msg, uint8_t failure_msg_len)
 {
     // exit immediately if not enabled
@@ -215,13 +216,12 @@ bool AP_Torqeedo::pre_arm_checks(char *failure_msg, uint8_t failure_msg_len)
         return true;
     }
 
-    const char *failure_prefix = "Torqeedo:";
     if (!_initialised) {
-        hal.util->snprintf(failure_msg, failure_msg_len, "%s not initialised", failure_prefix);
+        strncpy(failure_msg, "not initialised", failure_msg_len);
         return false;
     }
     if (!healthy()) {
-        hal.util->snprintf(failure_msg, failure_msg_len, "%s not healthy", failure_prefix);
+        strncpy(failure_msg, "not healthy", failure_msg_len);
         return false;
     }
     return true;
diff --git a/libraries/AP_Torqeedo/AP_Torqeedo.h b/libraries/AP_Torqeedo/AP_Torqeedo.h
index a4d6b18faf..b1d750e8b8 100644
--- a/libraries/AP_Torqeedo/AP_Torqeedo.h
+++ b/libraries/AP_Torqeedo/AP_Torqeedo.h
@@ -47,6 +47,7 @@ public:
     bool healthy();
 
     // run pre-arm check.  returns false on failure and fills in failure_msg
+    // any failure_msg returned will not include a prefix
     bool pre_arm_checks(char *failure_msg, uint8_t failure_msg_len);
 
     static const struct AP_Param::GroupInfo var_info[];