diff --git a/Marlin/src/Marlin.cpp b/Marlin/src/Marlin.cpp
index a5196ad15c..0de54efa78 100644
--- a/Marlin/src/Marlin.cpp
+++ b/Marlin/src/Marlin.cpp
@@ -361,10 +361,6 @@ void suicide() {
  ***************** GCode Handlers *****************
  **************************************************/
 
-#if ENABLED(NOZZLE_CLEAN_FEATURE)
-  #include "gcode/feature/clean/G12.h"
-#endif
-
 #if ENABLED(CNC_WORKSPACE_PLANES)
   #include "gcode/geometry/G17-G19.h"
 #endif
diff --git a/Marlin/src/gcode/feature/clean/G12.h b/Marlin/src/gcode/feature/clean/G12.cpp
similarity index 83%
rename from Marlin/src/gcode/feature/clean/G12.h
rename to Marlin/src/gcode/feature/clean/G12.cpp
index 35dea1220d..dbd9dd3ce3 100644
--- a/Marlin/src/gcode/feature/clean/G12.h
+++ b/Marlin/src/gcode/feature/clean/G12.cpp
@@ -20,10 +20,20 @@
  *
  */
 
+#include "../../../inc/MarlinConfig.h"
+
+#if ENABLED(NOZZLE_CLEAN_FEATURE)
+
+#include "../../../libs/nozzle.h"
+
+#include "../../gcode.h"
+#include "../../parser.h"
+#include "../../../module/motion.h"
+
 /**
  * G12: Clean the nozzle
  */
-void gcode_G12() {
+void GcodeSuite::G12() {
   // Don't allow nozzle cleaning without homing first
   if (axis_unhomed_error()) return;
 
@@ -34,3 +44,5 @@ void gcode_G12() {
 
   Nozzle::clean(pattern, strokes, radius, objects);
 }
+
+#endif // NOZZLE_CLEAN_FEATURE
diff --git a/Marlin/src/gcode/gcode.cpp b/Marlin/src/gcode/gcode.cpp
index a613d31810..471152942b 100644
--- a/Marlin/src/gcode/gcode.cpp
+++ b/Marlin/src/gcode/gcode.cpp
@@ -112,7 +112,6 @@ void GcodeSuite::dwell(millis_t time) {
 //
 // Placeholders for non-migrated codes
 //
-extern void gcode_G12();
 extern void gcode_G17();
 extern void gcode_G18();
 extern void gcode_G19();
@@ -313,7 +312,7 @@ void GcodeSuite::process_next_command() {
 
       #if ENABLED(NOZZLE_CLEAN_FEATURE)
         case 12:
-          gcode_G12(); // G12: Nozzle Clean
+          G12(); // G12: Nozzle Clean
           break;
       #endif // NOZZLE_CLEAN_FEATURE