diff --git a/OBD.NET/OBD.NET.Common/Devices/ELM327.cs b/OBD.NET/OBD.NET.Common/Devices/ELM327.cs
index b08d6ac..6b07d36 100644
--- a/OBD.NET/OBD.NET.Common/Devices/ELM327.cs
+++ b/OBD.NET/OBD.NET.Common/Devices/ELM327.cs
@@ -89,6 +89,7 @@ namespace OBD.NET.Devices
                 throw;
             }
         }
+        
 
         public virtual void SendCommand(ATCommand command)
         {
@@ -164,12 +165,11 @@ namespace OBD.NET.Devices
                 if (sendCloseProtocol)
                 {
                     SendCommand(ATCommand.CloseProtocol);
-                    //Thread.Sleep(500);
                 }
             }
             catch { }
 
-            _dataReceivedEventHandlers = null;
+            _dataReceivedEventHandlers.Clear();
 
             base.Dispose();
         }
diff --git a/OBD.NET/OBD.NET.Common/Devices/SerialDevice.cs b/OBD.NET/OBD.NET.Common/Devices/SerialDevice.cs
index 1d2f2f9..2ca4954 100644
--- a/OBD.NET/OBD.NET.Common/Devices/SerialDevice.cs
+++ b/OBD.NET/OBD.NET.Common/Devices/SerialDevice.cs
@@ -203,21 +203,22 @@ namespace OBD.NET.Devices
             while (!commandCancellationToken.IsCancellationRequested)
             {
                 string command = null;
-                commandQueue.TryTake(out command, Timeout.Infinite, commandCancellationToken.Token);
-                Logger?.WriteLine("Writing Command: '" + command.Replace('\r', '\'') + "'", OBDLogLevel.Verbose);
-
-                if (Connection.IsAsync)
+                if(commandQueue.TryTake(out command, Timeout.Infinite, commandCancellationToken.Token))
                 {
-                    await Connection.WriteAsync(Encoding.ASCII.GetBytes(command));
-                }
-                else
-                {
-                    Connection.Write(Encoding.ASCII.GetBytes(command));
+                    Logger?.WriteLine("Writing Command: '" + command.Replace('\r', '\'') + "'", OBDLogLevel.Verbose);
 
-                }
-                //wait for command to finish
-                commandFinishedEvent.WaitOne();
+                    if (Connection.IsAsync)
+                    {
+                        await Connection.WriteAsync(Encoding.ASCII.GetBytes(command));
+                    }
+                    else
+                    {
+                        Connection.Write(Encoding.ASCII.GetBytes(command));
 
+                    }
+                    //wait for command to finish
+                    commandFinishedEvent.WaitOne();   
+                }
             }
         }