diff --git a/library/build.gradle b/library/build.gradle
index 2e4bf03..216a79e 100644
--- a/library/build.gradle
+++ b/library/build.gradle
@@ -8,7 +8,7 @@ signing {
     sign configurations.archives
 }
 
-def lib_version = '1.4.2'
+def lib_version = '1.4.3'
 def user_name = 'wandersnail'
 def lib_group = 'cn.wandersnail'
 def lib_artifact = 'easyble-x'
diff --git a/library/src/main/java/cn/wandersnail/ble/AbstractScanner.java b/library/src/main/java/cn/wandersnail/ble/AbstractScanner.java
index 5008260..ff0a089 100644
--- a/library/src/main/java/cn/wandersnail/ble/AbstractScanner.java
+++ b/library/src/main/java/cn/wandersnail/ble/AbstractScanner.java
@@ -17,16 +17,17 @@
 import android.util.Log;
 import android.util.SparseArray;
 
+import androidx.annotation.CallSuper;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.annotation.RequiresApi;
+
 import java.lang.reflect.Method;
 import java.util.List;
 import java.util.Locale;
 import java.util.Set;
 import java.util.concurrent.CopyOnWriteArrayList;
 
-import androidx.annotation.CallSuper;
-import androidx.annotation.NonNull;
-import androidx.annotation.Nullable;
-import androidx.annotation.RequiresApi;
 import cn.wandersnail.ble.callback.ScanListener;
 import cn.wandersnail.ble.util.Logger;
 
@@ -221,7 +222,18 @@ void parseScanResult(BluetoothDevice device, boolean isConnectedBySys, @Nullable
     @Override
     public void startScan(@NonNull Context context) {
         synchronized (this) {
-            if (!isBtEnabled() || (getType() != ScannerType.CLASSIC && isScanning) || !isReady()) {
+            if (getType() != ScannerType.CLASSIC && isScanning) {
+                return;
+            }
+            if (!isReady()) {
+                String errorMsg = "Scanner not ready.";
+                handleScanCallback(false, null, false, ScanListener.ERROR_SCANNER_NOT_READY, errorMsg);
+                logger.log(Log.ERROR, Logger.TYPE_SCAN_STATE, errorMsg);
+            }
+            if (!isBtEnabled()) {
+                String errorMsg = "Bluetooth is not turned on.";
+                handleScanCallback(false, null, false, ScanListener.ERROR_BLUETOOTH_OFF, errorMsg);
+                logger.log(Log.ERROR, Logger.TYPE_SCAN_STATE, errorMsg);
                 return;
             }
             if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
diff --git a/library/src/main/java/cn/wandersnail/ble/ConnectionImpl.java b/library/src/main/java/cn/wandersnail/ble/ConnectionImpl.java
index f151164..358e057 100644
--- a/library/src/main/java/cn/wandersnail/ble/ConnectionImpl.java
+++ b/library/src/main/java/cn/wandersnail/ble/ConnectionImpl.java
@@ -943,6 +943,7 @@ private void handlePhyChange(boolean read, int txPhy, int rxPhy, int status) {
 
     private void handleGattStatusFailed(int status) {
         if (currentRequest != null) {
+            connHandler.removeMessages(MSG_REQUEST_TIMEOUT);//移除超时检测
             handleFailedCallback(currentRequest, REQUEST_FAIL_TYPE_GATT_STATUS_FAILED, status, false);
         }
     }
diff --git a/library/src/main/java/cn/wandersnail/ble/callback/ScanListener.java b/library/src/main/java/cn/wandersnail/ble/callback/ScanListener.java
index 0af5d4c..36f5240 100644
--- a/library/src/main/java/cn/wandersnail/ble/callback/ScanListener.java
+++ b/library/src/main/java/cn/wandersnail/ble/callback/ScanListener.java
@@ -33,6 +33,14 @@ public interface ScanListener {
      * 缺少连接权限。 {@link Manifest.permission#BLUETOOTH_CONNECT}
      */
     int ERROR_LACK_CONNECT_PERMISSION = 4;
+    /**
+     * 蓝牙未开启
+     */
+    int ERROR_BLUETOOTH_OFF = 5;
+    /**
+     * 扫描器未准备好
+     */
+    int ERROR_SCANNER_NOT_READY = 6;
     
 
     /**