diff --git a/src/ATBAPP/DeviceControllerDiag.cpp b/src/ATBAPP/DeviceControllerDiag.cpp
index fe4fb67..d7193cb 100644
--- a/src/ATBAPP/DeviceControllerDiag.cpp
+++ b/src/ATBAPP/DeviceControllerDiag.cpp
@@ -5,6 +5,8 @@
 #include <QUuid>
 #include <QDebug>
 
+#include <QProcess>
+
 #include "support/JSON.h"
 
 
@@ -18,6 +20,7 @@ DeviceControllerDiag::DeviceControllerDiag(PersistentData *pData, QObject *paren
     , lastState(DeviceController::State::INITIAL_STATE)
     , _isErrorState(false)
     , pData(pData)
+    , E255counter(0)
 {
     diagRequestTimeoutTimer = new QTimer(this);
     diagRequestTimeoutTimer->setInterval(1000*45);
@@ -104,14 +107,20 @@ void DeviceControllerDiag::private_startDiag()
         this->private_sendDiagEvent(DeviceController::State::E255);
         this->isRequestRunning  = false;
         this->flagInterruptDiag = false;
+        if (this->E255counter > 5) {
+            this->restartCArun();
+        }
+        else {
+            this->E255counter++;
 
-        // try it again, until success:
-        QTimer::singleShot(400, this, &DeviceControllerDiag::diagRequest);
-        /**
-         * But please note:
-         * - diag does currently not stop suspend (start a background task)
-         * - diag is called again in ModeOOO wokeup()
-         */
+            // try it again, until success:
+            QTimer::singleShot(400, this, &DeviceControllerDiag::diagRequest);
+            /**
+             * But please note:
+             * - diag does currently not stop suspend (start a background task)
+             * - diag is called again in ModeOOO wokeup()
+             */
+        }
         return;
     }
 
@@ -146,6 +155,8 @@ void DeviceControllerDiag::sys_superviseSystem()
         this->private_sendDiagEvent(DeviceController::State::E255);
         this->flagInterruptDiag = false;
         this->isRequestRunning  = false;
+        if (this->E255counter > 5) { this->restartCArun(); }
+                              else { this->E255counter++; }
         return;
     }
 
@@ -156,6 +167,8 @@ void DeviceControllerDiag::sys_superviseSystem()
         this->private_sendDiagEvent(DeviceController::State::E254);
         this->diagRequestTimeoutTimer->stop();
         this->isRequestRunning  = false;
+        if (this->E255counter > 5) { this->restartCArun(); }
+                              else { this->E255counter++; }
         return;
     }
 
@@ -168,7 +181,7 @@ void DeviceControllerDiag::sys_superviseSystem()
     {
         // noch keine Testergebnisse
         if (dynMaCond.startupTestIsRunning) {
-            // TODO?
+            qCritical() << "            startupTestIsRunning --> call again";
         }
 
 
@@ -599,3 +612,12 @@ void DeviceControllerDiag::private_sendDiagEvent(DeviceController::State result)
 }
 
 
+
+/**
+ * reset / restart / reinit deviceController
+ */
+void DeviceControllerDiag::restartCArun()
+{
+    this->E255counter = 0;
+    QProcess::startDetached("/bin/systemctl", {"restart", "carun"});
+}
diff --git a/src/ATBAPP/DeviceControllerDiag.h b/src/ATBAPP/DeviceControllerDiag.h
index 3555877..e89cc39 100644
--- a/src/ATBAPP/DeviceControllerDiag.h
+++ b/src/ATBAPP/DeviceControllerDiag.h
@@ -94,6 +94,11 @@ public slots:
      */
     void diagReInit();
 
+    /**
+     * reset / restart / reinit deviceController
+     */
+    void restartCArun();
+
 signals:
     void diagResponse(ATBMachineEvent* machineEvent);
 
@@ -118,6 +123,8 @@ private:
 
     PersistentData* pData;
 
+    int E255counter;
+
 private slots:
     void onDiagRequestTimeoutTimerTimeout();
 
@@ -126,7 +133,6 @@ private slots:
 
     void sys_superviseSystem();
 
-
 };
 
 #endif // DEVICECONTROLLERDIAG_H