diff --git a/gcode.h b/gcode.h
index 8a29aab..fc28d32 100644
--- a/gcode.h
+++ b/gcode.h
@@ -71,8 +71,9 @@
 #define MOTION_MODE_LINEAR 1 // G1
 #define MOTION_MODE_CW_ARC 2  // G2
 #define MOTION_MODE_CCW_ARC 3  // G3
-#define MOTION_MODE_PROBE 4 // G38.2
-#define MOTION_MODE_NONE 5 // G80
+#define MOTION_MODE_PROBE 4 // G38.2, G38.4
+#define MOTION_MODE_PROBE_NO_ERROR 5 // G38.3, G38.5
+#define MOTION_MODE_NONE 6 // G80
 
 // Modal Group G2: Plane select
 #define PLANE_SELECT_XY 0 // G17 (Default: Must be zero)