diff --git a/libraries/AP_KDECAN/AP_KDECAN.cpp b/libraries/AP_KDECAN/AP_KDECAN.cpp
index 76a8ee1cd0..4f6cc6b5a9 100644
--- a/libraries/AP_KDECAN/AP_KDECAN.cpp
+++ b/libraries/AP_KDECAN/AP_KDECAN.cpp
@@ -628,13 +628,12 @@ void AP_KDECAN::update()
 bool AP_KDECAN::pre_arm_check(char* reason, uint8_t reason_len)
 {
     if (!_enum_sem.take(1)) {
-        debug_can(AP_CANManager::LOG_DEBUG, "failed to get enumeration semaphore on read");
-        snprintf(reason, reason_len ,"Enumeration state unknown");
+        snprintf(reason, reason_len ,"enumeration state unknown");
         return false;
     }
 
     if (_enumeration_state != ENUMERATION_STOPPED) {
-        snprintf(reason, reason_len ,"Enumeration running");
+        snprintf(reason, reason_len, "enumeration running");
         _enum_sem.give();
         return false;
     }
@@ -652,17 +651,17 @@ bool AP_KDECAN::pre_arm_check(char* reason, uint8_t reason_len)
     uint8_t num_present_escs = __builtin_popcount(_esc_present_bitmask);
 
     if (num_present_escs < num_expected_motors) {
-        snprintf(reason, reason_len, "Too few ESCs detected");
+        snprintf(reason, reason_len, "too few ESCs detected (%u of %u)", (int)num_present_escs, (int)num_expected_motors);
         return false;
     }
 
     if (num_present_escs > num_expected_motors) {
-        snprintf(reason, reason_len, "Too many ESCs detected");
+        snprintf(reason, reason_len, "too many ESCs detected (%u > %u)", (int)num_present_escs, (int)num_expected_motors);
         return false;
     }
 
     if (_esc_max_node_id != num_expected_motors) {
-        snprintf(reason, reason_len, "Wrong node IDs, run enumeration");
+        snprintf(reason, reason_len, "wrong node IDs (%u!=%u), run enumeration", (int)_esc_max_node_id, (int)num_expected_motors);
         return false;
     }