diff --git a/buildroot/share/PlatformIO/scripts/preflight-checks.py b/buildroot/share/PlatformIO/scripts/preflight-checks.py
index 08856350d2ad..3f7c97af9d78 100644
--- a/buildroot/share/PlatformIO/scripts/preflight-checks.py
+++ b/buildroot/share/PlatformIO/scripts/preflight-checks.py
@@ -129,8 +129,10 @@ def rm_ofile(subdir, name):
         #
         if 'FILAMENT_RUNOUT_SENSOR' in env['MARLIN_FEATURES'] and 'NUM_RUNOUT_SENSORS' in env['MARLIN_FEATURES']:
             if env['MARLIN_FEATURES']['NUM_RUNOUT_SENSORS'].isdigit() and int(env['MARLIN_FEATURES']['NUM_RUNOUT_SENSORS']) > 1:
-                if 'FILAMENT_RUNOUT_SCRIPT' in env['MARLIN_FEATURES'] and "%c" not in env['MARLIN_FEATURES']['FILAMENT_RUNOUT_SCRIPT']:
-                    err = "ERROR: FILAMENT_RUNOUT_SCRIPT needs a %c parameter when NUM_RUNOUT_SENSORS is > 1"
-                    raise SystemExit(err)
+                if 'FILAMENT_RUNOUT_SCRIPT' in env['MARLIN_FEATURES']:
+                    frs = env['MARLIN_FEATURES']['FILAMENT_RUNOUT_SCRIPT']
+                    if "M600" in frs and "%c" not in frs:
+                        err = "ERROR: FILAMENT_RUNOUT_SCRIPT needs a %c parameter (e.g., \"M600 T%c\") when NUM_RUNOUT_SENSORS is > 1"
+                        raise SystemExit(err)
 
     sanity_check_target()