diff --git a/Marlin/Marlin.pde b/Marlin/Marlin.pde
index 34d50e3c46c9e28cb0cc93b2de0b9fac5cf5650e..c0fc8675c18803314ccedde5bc667d62f86fc2fd 100644
--- a/Marlin/Marlin.pde
+++ b/Marlin/Marlin.pde
@@ -695,7 +695,17 @@ inline void process_commands()
     case 109: 
     {// M109 - Wait for extruder heater to reach target.
         LCD_MESSAGEPGM("Heating...");
+        autotemp_enabled=false;
         if (code_seen('S')) setTargetHotend0(code_value());
+        #ifdef AUTOTEMP
+          if (code_seen('S')) autotemp_min=code_value();
+          if (code_seen('T')) autotemp_max=code_value();
+          if (code_seen('F')) 
+          {
+            autotemp_factor=code_value();
+            autotemp_enabled=true;
+          }
+        #endif
         
         setWatch();
         codenum = millis(); 
diff --git a/Marlin/planner.cpp b/Marlin/planner.cpp
index c27d58601764752d510a48b5bcf5b74aa5439aa7..0a226c66f79a2dedf8bbe75d85bb58480fea6225 100644
--- a/Marlin/planner.cpp
+++ b/Marlin/planner.cpp
@@ -87,7 +87,10 @@ static float previous_speed[4]; // Speed of previous path line segment
 static float previous_nominal_speed; // Nominal speed of previous path line segment
 
 #ifdef AUTOTEMP
-float high_e_speed=0;
+    float autotemp_max=250;
+    float autotemp_min=210;
+    float autotemp_factor=1;
+    bool autotemp_enabled=false;
 #endif
 
 
@@ -379,26 +382,29 @@ block_t *plan_get_current_block() {
 #ifdef AUTOTEMP
 void getHighESpeed()
 {
-  if(degTargetHotend0()+2<AUTOTEMP_MIN)  //probably temperature set to zero.
+  if(!autotemp_enabled)
+    return;
+  if(degTargetHotend0()+2<autotemp_min)  //probably temperature set to zero.
     return; //do nothing
+  
   float high=0;
   char block_index = block_buffer_tail;
   
   while(block_index != block_buffer_head) {
-    float se=block_buffer[block_index].speed_e;
+    float se=block_buffer[block_index].steps_e/float(block_buffer[block_index].step_event_count)*block_buffer[block_index].nominal_rate;
+    //se; units steps/sec;
     if(se>high)
     {
       high=se;
     }
     block_index = (block_index+1) & (BLOCK_BUFFER_SIZE - 1);
   }
-  high_e_speed=high*axis_steps_per_unit[E_AXIS]/(1000000.0);  //so it is independent of the esteps/mm. before 
    
-  float g=AUTOTEMP_MIN+high_e_speed*AUTOTEMP_FACTOR;
-  float t=constrain(AUTOTEMP_MIN,g,AUTOTEMP_MAX);
+  float g=autotemp_min+high*autotemp_factor;
+  float t=constrain(autotemp_min,g,autotemp_max);
   setTargetHotend0(t);
   SERIAL_ECHO_START;
-  SERIAL_ECHOPAIR("highe",high_e_speed);
+  SERIAL_ECHOPAIR("highe",high);
   SERIAL_ECHOPAIR(" t",t);
   SERIAL_ECHOLN("");
 }
diff --git a/Marlin/planner.h b/Marlin/planner.h
index be1587d6b805acef4431d1d0481f27e7ed5375dd..ec497d50648171974487cef8c20b1c55bdccb9da 100644
--- a/Marlin/planner.h
+++ b/Marlin/planner.h
@@ -92,7 +92,13 @@ extern float max_xy_jerk; //speed than can be stopped at once, if i understand c
 extern float max_z_jerk;
 extern float mintravelfeedrate;
 extern unsigned long axis_steps_per_sqr_second[NUM_AXIS];
+
+
 #ifdef AUTOTEMP
-extern float high_e_speed;
+    extern bool autotemp_enabled;
+    extern float autotemp_max;
+    extern float autotemp_min;
+    extern float autotemp_factor;
 #endif
+
 #endif