diff --git a/Marlin/src/core/language.h b/Marlin/src/core/language.h
index 696a5cb0a9..df3092fd99 100644
--- a/Marlin/src/core/language.h
+++ b/Marlin/src/core/language.h
@@ -168,7 +168,6 @@
 #define MSG_INVALID_E_STEPPER               "Invalid E stepper"
 #define MSG_E_STEPPER_NOT_SPECIFIED         "E stepper not specified"
 #define MSG_INVALID_SOLENOID                "Invalid solenoid"
-#define MSG_ERR_NO_THERMISTORS              "No thermistors - no temperature"
 #define MSG_M115_REPORT                     "FIRMWARE_NAME:Marlin " DETAILED_BUILD_VERSION " SOURCE_CODE_URL:" SOURCE_CODE_URL " PROTOCOL_VERSION:" PROTOCOL_VERSION " MACHINE_TYPE:" MACHINE_NAME " EXTRUDER_COUNT:" STRINGIFY(EXTRUDERS) " UUID:" MACHINE_UUID
 #define MSG_COUNT_X                         " Count X:"
 #define MSG_COUNT_A                         " Count A:"
diff --git a/Marlin/src/gcode/temperature/M105.cpp b/Marlin/src/gcode/temperature/M105.cpp
index bf11017a57..0483cb5210 100644
--- a/Marlin/src/gcode/temperature/M105.cpp
+++ b/Marlin/src/gcode/temperature/M105.cpp
@@ -39,7 +39,9 @@ void GcodeSuite::M105() {
       #endif
     );
   #else // !HAS_TEMP_SENSOR
-    SERIAL_ERROR_MSG(MSG_ERR_NO_THERMISTORS);
+    // Hosts such as printrun send M105 to check if firmware is responding.
+    SERIAL_ECHOPGM(MSG_OK);
+    SERIAL_ECHOPGM(" T:0");
   #endif
 
   SERIAL_EOL();