diff --git a/clock.c b/clock.c
index c83af71..80ee617 100644
--- a/clock.c
+++ b/clock.c
@@ -23,17 +23,21 @@
 	called from clock_10ms(), do not call directly
 */
 void clock_250ms() {
-	if (steptimeout > (30 * 4)) {
-		power_off();
-	}
-	else if (heaters_all_off())	{
-		uint8_t save_reg = SREG;
-		cli();
-		CLI_SEI_BUG_MEMORY_BARRIER();
-		steptimeout++;
-		MEMORY_BARRIER();
-		SREG = save_reg;
+	#ifndef	NO_AUTO_IDLE
+	if (temp_all_zero())	{
+		if (steptimeout > (30 * 4)) {
+			power_off();
+		}
+		else {
+			uint8_t save_reg = SREG;
+			cli();
+			CLI_SEI_BUG_MEMORY_BARRIER();
+			steptimeout++;
+			MEMORY_BARRIER();
+			SREG = save_reg;
+		}
 	}
+	#endif
 
 	ifclock(clock_flag_1s) {
 		if (DEBUG_POSITION && (debug_flags & DEBUG_POSITION)) {
diff --git a/temp.c b/temp.c
index df42697..b32b91b 100644
--- a/temp.c
+++ b/temp.c
@@ -326,6 +326,17 @@ uint16_t temp_get(temp_sensor_t index) {
 	return temp_sensors_runtime[index].last_read_temp;
 }
 
+uint8_t temp_all_zero() {
+	uint8_t i;
+	for (i = 0; i < NUM_TEMP_SENSORS; i++) {
+		if (temp_sensors[i].heater < NUM_HEATERS) {
+			if (temp_sensors_runtime[i].target_temp)
+				return 0;
+		}
+	}
+	return 255;
+}
+
 // extruder doesn't have sersendf_P
 #ifndef	EXTRUDER
 /// send temperatures to host
diff --git a/temp.h b/temp.h
index 68d1afe..2e185f8 100644
--- a/temp.h
+++ b/temp.h
@@ -41,6 +41,8 @@ uint8_t	temp_achieved(void);
 void temp_set(temp_sensor_t index, uint16_t temperature);
 uint16_t temp_get(temp_sensor_t index);
 
+uint8_t temp_all_zero(void);
+
 void temp_print(temp_sensor_t index);
 
 #endif	/* _TEMP_H */