M851 - report only without parameters

Marlin/src/gcode/probe/M851.cpp

@@ -29,16 +29,18 @@
 #include "../../module/probe.h"
 
 void GcodeSuite::M851() {
-  SERIAL_ECHO_START();
+  if (parser.seenval('Z')) {
-  SERIAL_ECHOPGM(MSG_PROBE_Z_OFFSET);
-  if (parser.seen('Z')) {
     const float value = parser.value_linear_units();
-    if (!WITHIN(value, Z_PROBE_OFFSET_RANGE_MIN, Z_PROBE_OFFSET_RANGE_MAX)) {
+    if (WITHIN(value, Z_PROBE_OFFSET_RANGE_MIN, Z_PROBE_OFFSET_RANGE_MAX))
-      SERIAL_ECHOLNPGM(" " MSG_Z_MIN " " STRINGIFY(Z_PROBE_OFFSET_RANGE_MIN) " " MSG_Z_MAX " " STRINGIFY(Z_PROBE_OFFSET_RANGE_MAX));
+      zprobe_zoffset = value;
-      return;
+    else {
+      SERIAL_ERROR_START();
+      SERIAL_ERRORLNPGM("?Z out of range (" STRINGIFY(Z_PROBE_OFFSET_RANGE_MIN) " to " STRINGIFY(Z_PROBE_OFFSET_RANGE_MAX) ")");
     }
-    zprobe_zoffset = value;
+    return;
   }
+  SERIAL_ECHO_START();
+  SERIAL_ECHOPGM(MSG_PROBE_Z_OFFSET);
   SERIAL_ECHOLNPAIR(": ", zprobe_zoffset);
 }