diff --git a/OBD.NET/OBD.NET.Common/Devices/SerialDevice.cs b/OBD.NET/OBD.NET.Common/Devices/SerialDevice.cs
index 021b1bf..e4623f2 100644
--- a/OBD.NET/OBD.NET.Common/Devices/SerialDevice.cs
+++ b/OBD.NET/OBD.NET.Common/Devices/SerialDevice.cs
@@ -197,6 +197,8 @@ namespace OBD.NET.Common.Devices
         /// </summary>
         private async void CommandWorker()
         {
+            CancellationToken cancellationToken = _commandCancellationToken.Token;
+
             while (!_commandCancellationToken.IsCancellationRequested)
             {
                 CurrentCommand = null;
@@ -206,7 +208,7 @@ namespace OBD.NET.Common.Devices
 
                 try
                 {
-                    if (_commandQueue.TryTake(out CurrentCommand, 10, _commandCancellationToken.Token))
+                    if (_commandQueue.TryTake(out CurrentCommand, 10, cancellationToken))
                     {
                         _queueSize--;
 
@@ -217,24 +219,19 @@ namespace OBD.NET.Common.Devices
                         else
                             Connection.Write(Encoding.ASCII.GetBytes(CurrentCommand.CommandText));
 
-                        //wait for command to finish or command canceled
-                        while (!(_commandFinishedEvent.WaitOne(50) || _commandCancellationToken.IsCancellationRequested))
-                        {
-                        }
+                        // wait for command to finish or command canceled
+                        while (!_commandFinishedEvent.WaitOne(50))
+                            cancellationToken.ThrowIfCancellationRequested();
                     }
                 }
-                catch (OperationCanceledException) { /*ignore, because it is thrown when the cancellation token is canceled*/}
-
-                // if canceled set all commands as completed (with null result)
-                if (_commandCancellationToken.IsCancellationRequested)
+                catch (OperationCanceledException)
                 {
                     CurrentCommand?.CommandResult.WaitHandle.Set();
-                    foreach (var cmd in _commandQueue)
-                    {
-                        cmd.CommandResult.WaitHandle.Set();
-                    }
                 }
             }
+
+            foreach (QueuedCommand cmd in _commandQueue)
+                cmd.CommandResult.WaitHandle.Set();
         }
 
         public void WaitQueue() => _queueEmptyEvent.WaitOne();