diff --git a/firmware/heater_control.cpp b/firmware/heater_control.cpp
index a0b52441..b4bfc778 100644
--- a/firmware/heater_control.cpp
+++ b/firmware/heater_control.cpp
@@ -20,6 +20,7 @@ void HeaterControllerBase::Configure(float targetTempC, float targetEsr)
     m_preheatTimer.reset();
     m_warmupTimer.reset();
     m_batteryStableTimer.reset();
+    m_closedLoopStableTimer.reset();
 }
 
 bool HeaterControllerBase::IsRunningClosedLoop() const
@@ -89,6 +90,7 @@ HeaterState HeaterControllerBase::GetNextState(HeaterState currentState, HeaterA
         case HeaterState::WarmupRamp:
             if (sensorTemp > closedLoopTemp)
             {
+                m_closedLoopStableTimer.reset();
                 return HeaterState::ClosedLoop;
             }
             else if (m_warmupTimer.hasElapsedSec(m_warmupTimeSec))
@@ -99,16 +101,22 @@ HeaterState HeaterControllerBase::GetNextState(HeaterState currentState, HeaterA
 
             break;
         case HeaterState::ClosedLoop:
-            // Check that the sensor's ESR is acceptable for normal operation
-            if (sensorTemp > overheatTemp)
-            {
-                SetFault(ch, Fault::SensorOverheat);
-                return HeaterState::Stopped;
-            }
-            else if (sensorTemp < underheatTemp)
-            {
-                SetFault(ch, Fault::SensorUnderheat);
-                return HeaterState::Stopped;
+            if (m_closedLoopStableTimer.hasElapsedSec(HEATER_CLOSED_LOOP_STAB_TIME)) {
+                // Check that the sensor's ESR is acceptable for normal operation
+                if (sensorTemp > overheatTemp)
+                {
+                    SetFault(ch, Fault::SensorOverheat);
+                    return HeaterState::Stopped;
+                }
+                else if (sensorTemp < underheatTemp)
+                {
+                    SetFault(ch, Fault::SensorUnderheat);
+                    return HeaterState::Stopped;
+                }
+            } else {
+                // give some time for stabilization...
+                // looks like heavy ramped Ipump affects sensorTemp measure
+                // and right after switch to closed loop sensorTemp drops below underhead threshold
             }
 
             break;
diff --git a/firmware/heater_control.h b/firmware/heater_control.h
index df0b2a2d..bb6aa7d7 100644
--- a/firmware/heater_control.h
+++ b/firmware/heater_control.h
@@ -73,6 +73,7 @@ class HeaterControllerBase : public IHeaterController
     Timer m_batteryStableTimer;
     Timer m_preheatTimer;
     Timer m_warmupTimer;
+    Timer m_closedLoopStableTimer;
 
     static const int batteryStabTimeCounter = HEATER_BATTERY_STAB_TIME / HEATER_CONTROL_PERIOD;
 };
diff --git a/firmware/wideband_config.h b/firmware/wideband_config.h
index 6e1000da..53ccc30d 100644
--- a/firmware/wideband_config.h
+++ b/firmware/wideband_config.h
@@ -42,6 +42,7 @@
 
 #define HEATER_PREHEAT_TIME 5
 #define HEATER_WARMUP_TIMEOUT 60
+#define HEATER_CLOSED_LOOP_STAB_TIME 5
 
 #define HEATER_BATTERY_STAB_TIME 0.5f
 // minimal battery voltage to start heating without CAN command