diff --git a/src/com/android/services/telephony/domainselection/EmergencyCallDomainSelector.java b/src/com/android/services/telephony/domainselection/EmergencyCallDomainSelector.java
index 570f942..30b9972 100644
--- a/src/com/android/services/telephony/domainselection/EmergencyCallDomainSelector.java
+++ b/src/com/android/services/telephony/domainselection/EmergencyCallDomainSelector.java
@@ -54,6 +54,7 @@
 import static android.telephony.PreciseDisconnectCause.EMERGENCY_PERM_FAILURE;
 import static android.telephony.PreciseDisconnectCause.EMERGENCY_TEMP_FAILURE;
 import static android.telephony.PreciseDisconnectCause.SERVICE_OPTION_NOT_AVAILABLE;
+import static android.telephony.TelephonyManager.DATA_CONNECTED;
 
 import android.annotation.NonNull;
 import android.content.Context;
@@ -211,13 +212,15 @@
     private final PowerManager.WakeLock mPartialWakeLock;
     private final CrossSimRedialingController mCrossSimRedialingController;
     private final CarrierConfigHelper mCarrierConfigHelper;
+    private final EmergencyCallbackModeHelper mEcbmHelper;
 
     /** Constructor. */
     public EmergencyCallDomainSelector(Context context, int slotId, int subId,
             @NonNull Looper looper, @NonNull ImsStateTracker imsStateTracker,
             @NonNull DestroyListener destroyListener,
             @NonNull CrossSimRedialingController csrController,
-            @NonNull CarrierConfigHelper carrierConfigHelper) {
+            @NonNull CarrierConfigHelper carrierConfigHelper,
+            @NonNull EmergencyCallbackModeHelper ecbmHelper) {
         super(context, slotId, subId, looper, imsStateTracker, destroyListener, TAG);
 
         mImsStateTracker.addBarringInfoListener(this);
@@ -228,6 +231,7 @@
 
         mCrossSimRedialingController = csrController;
         mCarrierConfigHelper = carrierConfigHelper;
+        mEcbmHelper = ecbmHelper;
         acquireWakeLock();
     }
 
@@ -630,7 +634,8 @@
             return;
         }
 
-        if (isWifiPreferred()) {
+        if (isWifiPreferred()
+                || isInEmergencyCallbackModeOnWlan()) {
             onWlanSelected();
             return;
         }
@@ -1545,6 +1550,12 @@
         }
     }
 
+    private boolean isInEmergencyCallbackModeOnWlan() {
+        return mEcbmHelper.isInEmergencyCallbackMode(getSlotId())
+                && mEcbmHelper.getTransportType(getSlotId()) == TRANSPORT_TYPE_WLAN
+                && mEcbmHelper.getDataConnectionState(getSlotId()) == DATA_CONNECTED;
+    }
+
     private void selectDomainForTestEmergencyNumber() {
         logi("selectDomainForTestEmergencyNumber");
         if (isImsRegisteredWithVoiceCapability()) {
diff --git a/src/com/android/services/telephony/domainselection/EmergencyCallbackModeHelper.java b/src/com/android/services/telephony/domainselection/EmergencyCallbackModeHelper.java
new file mode 100644
index 0000000..e42dfe7
--- /dev/null
+++ b/src/com/android/services/telephony/domainselection/EmergencyCallbackModeHelper.java
@@ -0,0 +1,235 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.services.telephony.domainselection;
+
+import static android.telephony.CarrierConfigManager.ImsEmergency.KEY_EMERGENCY_CALLBACK_MODE_SUPPORTED_BOOL;
+import static android.telephony.SubscriptionManager.EXTRA_SLOT_INDEX;
+import static android.telephony.SubscriptionManager.INVALID_SIM_SLOT_INDEX;
+import static android.telephony.TelephonyManager.ACTION_EMERGENCY_CALLBACK_MODE_CHANGED;
+import static android.telephony.TelephonyManager.EXTRA_PHONE_IN_ECM_STATE;
+
+import android.annotation.NonNull;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.os.Handler;
+import android.os.Looper;
+import android.os.Message;
+import android.os.PersistableBundle;
+import android.os.SystemProperties;
+import android.telephony.AccessNetworkConstants;
+import android.telephony.CarrierConfigManager;
+import android.telephony.PreciseDataConnectionState;
+import android.telephony.TelephonyCallback;
+import android.telephony.TelephonyManager;
+import android.telephony.data.ApnSetting;
+import android.util.ArrayMap;
+import android.util.Log;
+
+/** Helper class to cache emergency data connection state. */
+public class EmergencyCallbackModeHelper extends Handler {
+    private static final String TAG = "EmergencyCallbackModeHelper";
+    private static final boolean DBG = (SystemProperties.getInt("ro.debuggable", 0) == 1);
+
+    /**
+     * TelephonyCallback used to monitor ePDN state.
+     */
+    private static final class DataConnectionStateListener extends TelephonyCallback
+            implements TelephonyCallback.PreciseDataConnectionStateListener {
+
+        private final Handler mHandler;
+        private final TelephonyManager mTelephonyManager;
+        private final int mSubId;
+        private int mTransportType = AccessNetworkConstants.TRANSPORT_TYPE_INVALID;
+        private int mState = TelephonyManager.DATA_UNKNOWN;
+
+        DataConnectionStateListener(Handler handler, TelephonyManager tm, int subId) {
+            mHandler = handler;
+            mTelephonyManager = tm;
+            mSubId = subId;
+        }
+
+        @Override
+        public void onPreciseDataConnectionStateChanged(
+                @NonNull PreciseDataConnectionState dataConnectionState) {
+            ApnSetting apnSetting = dataConnectionState.getApnSetting();
+            if ((apnSetting == null)
+                    || ((apnSetting.getApnTypeBitmask() | ApnSetting.TYPE_EMERGENCY) == 0)) {
+                return;
+            }
+            mTransportType = dataConnectionState.getTransportType();
+            mState = dataConnectionState.getState();
+            Log.i(TAG, "onPreciseDataConnectionStateChanged ePDN state=" + mState
+                    + ", transport=" + mTransportType);
+        }
+
+        public void registerTelephonyCallback() {
+            TelephonyManager tm = mTelephonyManager.createForSubscriptionId(mSubId);
+            tm.registerTelephonyCallback(mHandler::post, this);
+        }
+
+        public void unregisterTelephonyCallback() {
+            mTelephonyManager.unregisterTelephonyCallback(this);
+        }
+
+        public int getSubId() {
+            return mSubId;
+        }
+
+        public int getTransportType() {
+            return mTransportType;
+        }
+
+        public int getState() {
+            return mState;
+        }
+    }
+
+    private final Context mContext;
+    private final TelephonyManager mTelephonyManager;
+    private final CarrierConfigManager mConfigManager;
+
+    private final ArrayMap<Integer, DataConnectionStateListener>
+            mDataConnectionStateListeners = new ArrayMap<>();
+
+    private final CarrierConfigManager.CarrierConfigChangeListener mCarrierConfigChangeListener =
+            (slotIndex, subId, carrierId, specificCarrierId) -> onCarrierConfigChanged(
+                    slotIndex, subId, carrierId);
+
+    /**
+     * Creates an instance.
+     *
+     * @param context The Context this is associated with.
+     * @param looper The Looper to run the EmergencyCallbackModeHelper.
+     */
+    public EmergencyCallbackModeHelper(@NonNull Context context, @NonNull Looper looper) {
+        super(looper);
+
+        mContext = context;
+        mTelephonyManager = context.getSystemService(TelephonyManager.class);
+        mConfigManager = context.getSystemService(CarrierConfigManager.class);
+        mConfigManager.registerCarrierConfigChangeListener(this::post,
+                mCarrierConfigChangeListener);
+    }
+
+    /**
+     * Returns whether it is in emergency callback mode.
+     *
+     * @param slotIndex The logical SIM slot index.
+     * @return true if it is in emergency callback mode.
+     */
+    public boolean isInEmergencyCallbackMode(int slotIndex) {
+        DataConnectionStateListener listener =
+                mDataConnectionStateListeners.get(Integer.valueOf(slotIndex));
+        if (listener == null) return false;
+
+        Intent intent = mContext.registerReceiver(null,
+                new IntentFilter(ACTION_EMERGENCY_CALLBACK_MODE_CHANGED));
+        if (intent != null
+                && ACTION_EMERGENCY_CALLBACK_MODE_CHANGED.equals(intent.getAction())) {
+            boolean inEcm = intent.getBooleanExtra(EXTRA_PHONE_IN_ECM_STATE, false);
+            int index = intent.getIntExtra(EXTRA_SLOT_INDEX, INVALID_SIM_SLOT_INDEX);
+            Log.i(TAG, "isInEmergencyCallbackMode inEcm=" + inEcm + ", slotIndex=" + index);
+            return inEcm && (slotIndex == index);
+        }
+        return false;
+    }
+
+    /**
+     * Returns the transport type of emergency data connection.
+     *
+     * @param slotIndex The logical SIM slot index.
+     * @return the transport type of emergency data connection.
+     */
+    public int getTransportType(int slotIndex) {
+        DataConnectionStateListener listener =
+                mDataConnectionStateListeners.get(Integer.valueOf(slotIndex));
+        if (listener == null) return AccessNetworkConstants.TRANSPORT_TYPE_INVALID;
+        Log.i(TAG, "getTransportType " + listener.getTransportType());
+        return listener.getTransportType();
+    }
+
+    /**
+     * Returns the data connection state.
+     *
+     * @param slotIndex The logical SIM slot index.
+     * @return the data connection state.
+     */
+    public int getDataConnectionState(int slotIndex) {
+        DataConnectionStateListener listener =
+                mDataConnectionStateListeners.get(Integer.valueOf(slotIndex));
+        if (listener == null) return TelephonyManager.DATA_UNKNOWN;
+        Log.i(TAG, "getDataConnectionState " + listener.getState());
+        return listener.getState();
+    }
+
+    @Override
+    public void handleMessage(Message msg) {
+        switch(msg.what) {
+            default:
+                super.handleMessage(msg);
+                break;
+        }
+    }
+
+    private void onCarrierConfigChanged(int slotIndex, int subId, int carrierId) {
+        Log.i(TAG, "onCarrierConfigChanged slotIndex=" + slotIndex
+                + ", subId=" + subId + ", carrierId=" + carrierId);
+
+        if (slotIndex < 0) {
+            return;
+        }
+
+        PersistableBundle b = mConfigManager.getConfigForSubId(subId,
+                KEY_EMERGENCY_CALLBACK_MODE_SUPPORTED_BOOL);
+
+        if (b.getBoolean(KEY_EMERGENCY_CALLBACK_MODE_SUPPORTED_BOOL)) {
+            // ECBM supported
+            DataConnectionStateListener listener =
+                    mDataConnectionStateListeners.get(Integer.valueOf(slotIndex));
+
+            // Remove stale listener.
+            if (listener != null && listener.getSubId() != subId) {
+                listener.unregisterTelephonyCallback();
+                listener = null;
+            }
+
+            if (listener == null) {
+                listener = new DataConnectionStateListener(this, mTelephonyManager, subId);
+                listener.registerTelephonyCallback();
+                mDataConnectionStateListeners.put(Integer.valueOf(slotIndex), listener);
+                Log.i(TAG, "onCarrierConfigChanged register callback");
+            }
+        } else {
+            // ECBM not supported
+            DataConnectionStateListener listener =
+                    mDataConnectionStateListeners.get(Integer.valueOf(slotIndex));
+            if (listener != null) {
+                listener.unregisterTelephonyCallback();
+                mDataConnectionStateListeners.remove(Integer.valueOf(slotIndex));
+                Log.i(TAG, "onCarrierConfigChanged unregister callback");
+            }
+        }
+    }
+
+    /** Destroys the instance. */
+    public void destroy() {
+        if (DBG) Log.d(TAG, "destroy");
+        mConfigManager.unregisterCarrierConfigChangeListener(mCarrierConfigChangeListener);
+        mDataConnectionStateListeners.forEach((k, v) -> v.unregisterTelephonyCallback());
+    }
+}
diff --git a/src/com/android/services/telephony/domainselection/TelephonyDomainSelectionService.java b/src/com/android/services/telephony/domainselection/TelephonyDomainSelectionService.java
index a215c4f..fca5966 100644
--- a/src/com/android/services/telephony/domainselection/TelephonyDomainSelectionService.java
+++ b/src/com/android/services/telephony/domainselection/TelephonyDomainSelectionService.java
@@ -74,7 +74,8 @@
                 @NonNull ImsStateTracker imsStateTracker,
                 @NonNull DomainSelectorBase.DestroyListener listener,
                 @NonNull CrossSimRedialingController crossSimRedialingController,
-                @NonNull CarrierConfigHelper carrierConfigHelper);
+                @NonNull CarrierConfigHelper carrierConfigHelper,
+                @NonNull EmergencyCallbackModeHelper emergencyCallbackModeHelper);
     }
 
     private static final class DefaultDomainSelectorFactory implements DomainSelectorFactory {
@@ -84,7 +85,8 @@
                 @NonNull ImsStateTracker imsStateTracker,
                 @NonNull DomainSelectorBase.DestroyListener listener,
                 @NonNull CrossSimRedialingController crossSimRedialingController,
-                @NonNull CarrierConfigHelper carrierConfigHelper) {
+                @NonNull CarrierConfigHelper carrierConfigHelper,
+                @NonNull EmergencyCallbackModeHelper emergencyCallbackModeHelper) {
             DomainSelectorBase selector = null;
 
             logi("create-DomainSelector: slotId=" + slotId + ", subId=" + subId
@@ -96,7 +98,7 @@
                     if (isEmergency) {
                         selector = new EmergencyCallDomainSelector(context, slotId, subId, looper,
                                 imsStateTracker, listener, crossSimRedialingController,
-                                carrierConfigHelper);
+                                carrierConfigHelper, emergencyCallbackModeHelper);
                     } else {
                         selector = new NormalCallDomainSelector(context, slotId, subId, looper,
                                 imsStateTracker, listener);
@@ -201,17 +203,19 @@
     private Handler mServiceHandler;
     private CrossSimRedialingController mCrossSimRedialingController;
     private CarrierConfigHelper mCarrierConfigHelper;
+    private EmergencyCallbackModeHelper mEmergencyCallbackModeHelper;
 
     /** Default constructor. */
     public TelephonyDomainSelectionService() {
-        this(ImsStateTracker::new, new DefaultDomainSelectorFactory(), null);
+        this(ImsStateTracker::new, new DefaultDomainSelectorFactory(), null, null);
     }
 
     @VisibleForTesting
     protected TelephonyDomainSelectionService(
             @NonNull ImsStateTrackerFactory imsStateTrackerFactory,
             @NonNull DomainSelectorFactory domainSelectorFactory,
-            @Nullable CarrierConfigHelper carrierConfigHelper) {
+            @Nullable CarrierConfigHelper carrierConfigHelper,
+            @Nullable EmergencyCallbackModeHelper ecbmHelper) {
         mImsStateTrackerFactory = imsStateTrackerFactory;
         mDomainSelectorFactory = domainSelectorFactory;
         mCarrierConfigHelper = carrierConfigHelper;
@@ -242,6 +246,9 @@
         if (mCarrierConfigHelper == null) {
             mCarrierConfigHelper = new CarrierConfigHelper(mContext, getLooper());
         }
+        if (mEmergencyCallbackModeHelper == null) {
+            mEmergencyCallbackModeHelper = new EmergencyCallbackModeHelper(mContext, getLooper());
+        }
 
         logi("TelephonyDomainSelectionService created");
     }
@@ -290,6 +297,11 @@
             mCarrierConfigHelper = null;
         }
 
+        if (mEmergencyCallbackModeHelper != null) {
+            mEmergencyCallbackModeHelper.destroy();
+            mEmergencyCallbackModeHelper = null;
+        }
+
         if (mServiceHandler != null) {
             mServiceHandler.getLooper().quit();
             mServiceHandler = null;
@@ -312,7 +324,7 @@
         ImsStateTracker ist = getImsStateTracker(slotId);
         DomainSelectorBase selector = mDomainSelectorFactory.create(mContext, slotId, subId,
                 selectorType, isEmergency, getLooper(), ist, mDestroyListener,
-                mCrossSimRedialingController, mCarrierConfigHelper);
+                mCrossSimRedialingController, mCarrierConfigHelper, mEmergencyCallbackModeHelper);
 
         if (selector != null) {
             // Ensures that ImsStateTracker is started before selecting the domain if not started
diff --git a/tests/src/com/android/services/telephony/domainselection/CarrierConfigHelperTest.java b/tests/src/com/android/services/telephony/domainselection/CarrierConfigHelperTest.java
index 5d4fe17..8f51dab 100644
--- a/tests/src/com/android/services/telephony/domainselection/CarrierConfigHelperTest.java
+++ b/tests/src/com/android/services/telephony/domainselection/CarrierConfigHelperTest.java
@@ -32,7 +32,6 @@
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.doReturn;
 import static org.mockito.Mockito.verify;
-import static org.mockito.Mockito.when;
 
 import android.content.Context;
 import android.content.SharedPreferences;
@@ -68,11 +67,11 @@
     private static final int SUB_1 = 1;
     private static final int TEST_SIM_CARRIER_ID = 1911;
 
-    @Mock private Context mContext;
     @Mock private SharedPreferences mSharedPreferences;
     @Mock private SharedPreferences.Editor mEditor;
     @Mock private Resources mResources;
 
+    private Context mContext;
     private HandlerThread mHandlerThread;
     private TestableLooper mLooper;
     private CarrierConfigHelper mCarrierConfigHelper;
diff --git a/tests/src/com/android/services/telephony/domainselection/EmergencyCallDomainSelectorTest.java b/tests/src/com/android/services/telephony/domainselection/EmergencyCallDomainSelectorTest.java
index 8cad6a4..a015783 100644
--- a/tests/src/com/android/services/telephony/domainselection/EmergencyCallDomainSelectorTest.java
+++ b/tests/src/com/android/services/telephony/domainselection/EmergencyCallDomainSelectorTest.java
@@ -16,6 +16,8 @@
 
 package com.android.services.telephony.domainselection;
 
+import static android.telephony.AccessNetworkConstants.TRANSPORT_TYPE_WLAN;
+import static android.telephony.AccessNetworkConstants.TRANSPORT_TYPE_WWAN;
 import static android.telephony.AccessNetworkConstants.AccessNetworkType.EUTRAN;
 import static android.telephony.AccessNetworkConstants.AccessNetworkType.GERAN;
 import static android.telephony.AccessNetworkConstants.AccessNetworkType.NGRAN;
@@ -53,6 +55,7 @@
 import static android.telephony.NetworkRegistrationInfo.REGISTRATION_STATE_HOME;
 import static android.telephony.NetworkRegistrationInfo.REGISTRATION_STATE_UNKNOWN;
 import static android.telephony.PreciseDisconnectCause.SERVICE_OPTION_NOT_AVAILABLE;
+import static android.telephony.TelephonyManager.DATA_CONNECTED;
 
 import static com.android.services.telephony.domainselection.EmergencyCallDomainSelector.MSG_MAX_CELLULAR_TIMEOUT;
 import static com.android.services.telephony.domainselection.EmergencyCallDomainSelector.MSG_NETWORK_SCAN_TIMEOUT;
@@ -69,6 +72,7 @@
 import static org.mockito.Mockito.doAnswer;
 import static org.mockito.Mockito.doReturn;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
@@ -147,6 +151,7 @@
     @Mock private ProvisioningManager mProvisioningManager;
     @Mock private CrossSimRedialingController mCsrdCtrl;
     @Mock private CarrierConfigHelper mCarrierConfigHelper;
+    @Mock private EmergencyCallbackModeHelper mEcbmHelper;
     @Mock private Resources mResources;
 
     private Context mContext;
@@ -2246,6 +2251,93 @@
         verifyCsDialed();
     }
 
+    @Test
+    public void testWhileInEcbmOnWwan() throws Exception {
+        createSelector(SLOT_0_SUB_ID);
+        unsolBarringInfoChanged(false);
+
+        doReturn(true).when(mEcbmHelper).isInEmergencyCallbackMode(anyInt());
+        doReturn(TRANSPORT_TYPE_WWAN).when(mEcbmHelper).getTransportType(anyInt());
+        doReturn(DATA_CONNECTED).when(mEcbmHelper).getDataConnectionState(anyInt());
+
+        EmergencyRegResult regResult = getEmergencyRegResult(UNKNOWN, REGISTRATION_STATE_UNKNOWN,
+                0, false, false, 0, 0, "", "");
+        SelectionAttributes attr = getSelectionAttributes(SLOT_0, SLOT_0_SUB_ID, regResult);
+        mDomainSelector.selectDomain(attr, mTransportSelectorCallback);
+        processAllMessages();
+
+        bindImsServiceUnregistered();
+        processAllMessages();
+
+        verify(mTransportSelectorCallback, never()).onWlanSelected(anyBoolean());
+        verify(mTransportSelectorCallback).onWwanSelected(any());
+    }
+
+    @Test
+    public void testWhileInEcbmOnWlanConnected() throws Exception {
+        createSelector(SLOT_0_SUB_ID);
+        unsolBarringInfoChanged(false);
+
+        doReturn(true).when(mEcbmHelper).isInEmergencyCallbackMode(anyInt());
+        doReturn(TRANSPORT_TYPE_WLAN).when(mEcbmHelper).getTransportType(anyInt());
+        doReturn(DATA_CONNECTED).when(mEcbmHelper).getDataConnectionState(anyInt());
+
+        EmergencyRegResult regResult = getEmergencyRegResult(UNKNOWN, REGISTRATION_STATE_UNKNOWN,
+                0, false, false, 0, 0, "", "");
+        SelectionAttributes attr = getSelectionAttributes(SLOT_0, SLOT_0_SUB_ID, regResult);
+        mDomainSelector.selectDomain(attr, mTransportSelectorCallback);
+        processAllMessages();
+
+        bindImsServiceUnregistered();
+        processAllMessages();
+
+        verify(mTransportSelectorCallback).onWlanSelected(anyBoolean());
+        verify(mTransportSelectorCallback, never()).onWwanSelected(any());
+    }
+
+    @Test
+    public void testWhileInEcbmOnWlanNotConnected() throws Exception {
+        createSelector(SLOT_0_SUB_ID);
+        unsolBarringInfoChanged(false);
+
+        doReturn(true).when(mEcbmHelper).isInEmergencyCallbackMode(anyInt());
+        doReturn(TRANSPORT_TYPE_WLAN).when(mEcbmHelper).getTransportType(anyInt());
+
+        EmergencyRegResult regResult = getEmergencyRegResult(UNKNOWN, REGISTRATION_STATE_UNKNOWN,
+                0, false, false, 0, 0, "", "");
+        SelectionAttributes attr = getSelectionAttributes(SLOT_0, SLOT_0_SUB_ID, regResult);
+        mDomainSelector.selectDomain(attr, mTransportSelectorCallback);
+        processAllMessages();
+
+        bindImsServiceUnregistered();
+        processAllMessages();
+
+        verify(mTransportSelectorCallback, never()).onWlanSelected(anyBoolean());
+        verify(mTransportSelectorCallback).onWwanSelected(any());
+    }
+
+    @Test
+    public void testNotInEcbmOnWlanConnected() throws Exception {
+        createSelector(SLOT_0_SUB_ID);
+        unsolBarringInfoChanged(false);
+
+        doReturn(false).when(mEcbmHelper).isInEmergencyCallbackMode(anyInt());
+        doReturn(TRANSPORT_TYPE_WLAN).when(mEcbmHelper).getTransportType(anyInt());
+        doReturn(DATA_CONNECTED).when(mEcbmHelper).getDataConnectionState(anyInt());
+
+        EmergencyRegResult regResult = getEmergencyRegResult(UNKNOWN, REGISTRATION_STATE_UNKNOWN,
+                0, false, false, 0, 0, "", "");
+        SelectionAttributes attr = getSelectionAttributes(SLOT_0, SLOT_0_SUB_ID, regResult);
+        mDomainSelector.selectDomain(attr, mTransportSelectorCallback);
+        processAllMessages();
+
+        bindImsServiceUnregistered();
+        processAllMessages();
+
+        verify(mTransportSelectorCallback, never()).onWlanSelected(anyBoolean());
+        verify(mTransportSelectorCallback).onWwanSelected(any());
+    }
+
     private void setupForScanListTest(PersistableBundle bundle) throws Exception {
         setupForScanListTest(bundle, false);
     }
@@ -2319,7 +2411,7 @@
     private void createSelector(int subId) throws Exception {
         mDomainSelector = new EmergencyCallDomainSelector(
                 mContext, SLOT_0, subId, mHandlerThread.getLooper(),
-                mImsStateTracker, mDestroyListener, mCsrdCtrl, mCarrierConfigHelper);
+                mImsStateTracker, mDestroyListener, mCsrdCtrl, mCarrierConfigHelper, mEcbmHelper);
         mDomainSelector.clearResourceConfiguration();
         replaceInstance(DomainSelectorBase.class,
                 "mWwanSelectorCallback", mDomainSelector, mWwanSelectorCallback);
diff --git a/tests/src/com/android/services/telephony/domainselection/EmergencyCallbackModeHelperTest.java b/tests/src/com/android/services/telephony/domainselection/EmergencyCallbackModeHelperTest.java
new file mode 100644
index 0000000..9a4e0d8
--- /dev/null
+++ b/tests/src/com/android/services/telephony/domainselection/EmergencyCallbackModeHelperTest.java
@@ -0,0 +1,305 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.services.telephony.domainselection;
+
+import static android.telephony.CarrierConfigManager.ImsEmergency.KEY_EMERGENCY_CALLBACK_MODE_SUPPORTED_BOOL;
+
+import static junit.framework.Assert.assertFalse;
+import static junit.framework.Assert.assertTrue;
+import static junit.framework.Assert.assertNotNull;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyInt;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.os.HandlerThread;
+import android.os.Looper;
+import android.os.PersistableBundle;
+import android.telephony.CarrierConfigManager;
+import android.telephony.SubscriptionManager;
+import android.telephony.TelephonyCallback;
+import android.telephony.TelephonyManager;
+import android.testing.TestableLooper;
+import android.util.Log;
+
+import com.android.TestContext;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.ArgumentCaptor;
+import org.mockito.MockitoAnnotations;
+
+import java.util.concurrent.Executor;
+
+/**
+ * Unit tests for EmergencyCallbackModeHelper
+ */
+public class EmergencyCallbackModeHelperTest {
+    private static final String TAG = "EmergencyCallbackModeHelperTest";
+
+    private static final int SLOT_0 = 0;
+    private static final int SLOT_1 = 1;
+    private static final int SUB_1 = 1;
+    private static final int SUB_2 = 2;
+
+    private Context mContext;
+    private HandlerThread mHandlerThread;
+    private TestableLooper mLooper;
+    private EmergencyCallbackModeHelper mEcbmHelper;
+    private CarrierConfigManager mCarrierConfigManager;
+    private TelephonyManager mTelephonyManager;
+
+    @Before
+    public void setUp() throws Exception {
+        MockitoAnnotations.initMocks(this);
+        mContext = new TestContext() {
+            private Intent mIntent;
+
+            @Override
+            public String getSystemServiceName(Class<?> serviceClass) {
+                if (serviceClass == TelephonyManager.class) {
+                    return Context.TELEPHONY_SERVICE;
+                } else if (serviceClass == CarrierConfigManager.class) {
+                    return Context.CARRIER_CONFIG_SERVICE;
+                }
+                return super.getSystemServiceName(serviceClass);
+            }
+
+            @Override
+            public String getOpPackageName() {
+                return "";
+            }
+
+            @Override
+            public Intent registerReceiver(BroadcastReceiver receiver, IntentFilter filter) {
+                return mIntent;
+            }
+
+            @Override
+            public void sendStickyBroadcast(Intent intent) {
+                mIntent = intent;
+            }
+        };
+
+        if (Looper.myLooper() == null) {
+            Looper.prepare();
+        }
+
+        mHandlerThread = new HandlerThread("EmergencyCallbackModeHelperTest");
+        mHandlerThread.start();
+
+        try {
+            mLooper = new TestableLooper(mHandlerThread.getLooper());
+        } catch (Exception e) {
+            logd("Unable to create looper from handler.");
+        }
+
+        mCarrierConfigManager = mContext.getSystemService(CarrierConfigManager.class);
+        mTelephonyManager = mContext.getSystemService(TelephonyManager.class);
+        doReturn(mTelephonyManager).when(mTelephonyManager).createForSubscriptionId(anyInt());
+
+        mEcbmHelper = new EmergencyCallbackModeHelper(mContext, mHandlerThread.getLooper());
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        if (mEcbmHelper != null) {
+            mEcbmHelper.destroy();
+            mEcbmHelper = null;
+        }
+
+        if (mLooper != null) {
+            mLooper.destroy();
+            mLooper = null;
+        }
+    }
+
+    @Test
+    public void testInit() throws Exception {
+        ArgumentCaptor<CarrierConfigManager.CarrierConfigChangeListener> callbackCaptor =
+                ArgumentCaptor.forClass(CarrierConfigManager.CarrierConfigChangeListener.class);
+        ArgumentCaptor<Executor> executorCaptor = ArgumentCaptor.forClass(Executor.class);
+
+        verify(mCarrierConfigManager).registerCarrierConfigChangeListener(executorCaptor.capture(),
+                callbackCaptor.capture());
+        assertNotNull(executorCaptor.getValue());
+        assertNotNull(callbackCaptor.getValue());
+    }
+
+    @Test
+    public void testEmergencyCallbackModeNotSupported() throws Exception {
+        ArgumentCaptor<CarrierConfigManager.CarrierConfigChangeListener> callbackCaptor =
+                ArgumentCaptor.forClass(CarrierConfigManager.CarrierConfigChangeListener.class);
+
+        verify(mCarrierConfigManager).registerCarrierConfigChangeListener(any(),
+                callbackCaptor.capture());
+
+        CarrierConfigManager.CarrierConfigChangeListener callback = callbackCaptor.getValue();
+
+        assertNotNull(callback);
+
+        // ECBM not supported
+        PersistableBundle b = getPersistableBundle(false);
+        doReturn(b).when(mCarrierConfigManager).getConfigForSubId(anyInt(), anyString());
+        callback.onCarrierConfigChanged(SLOT_0, SUB_1, 0, 0);
+
+        // No TelephonyCallback registered
+        verify(mTelephonyManager, never()).registerTelephonyCallback(any(), any());
+    }
+
+    @Test
+    public void testEmergencyCallbackModeSupported() throws Exception {
+        ArgumentCaptor<CarrierConfigManager.CarrierConfigChangeListener> callbackCaptor =
+                ArgumentCaptor.forClass(CarrierConfigManager.CarrierConfigChangeListener.class);
+
+        verify(mCarrierConfigManager).registerCarrierConfigChangeListener(any(),
+                callbackCaptor.capture());
+
+        CarrierConfigManager.CarrierConfigChangeListener callback = callbackCaptor.getValue();
+
+        assertNotNull(callback);
+
+        // ECBM supported
+        PersistableBundle b = getPersistableBundle(true);
+        doReturn(b).when(mCarrierConfigManager).getConfigForSubId(anyInt(), anyString());
+        callback.onCarrierConfigChanged(SLOT_0, SUB_1, 0, 0);
+
+        verify(mTelephonyManager).createForSubscriptionId(eq(SUB_1));
+
+        ArgumentCaptor<TelephonyCallback> telephonyCallbackCaptor =
+                ArgumentCaptor.forClass(TelephonyCallback.class);
+
+        // TelephonyCallback registered
+        verify(mTelephonyManager).registerTelephonyCallback(any(),
+                telephonyCallbackCaptor.capture());
+
+        assertNotNull(telephonyCallbackCaptor.getValue());
+    }
+
+    @Test
+    public void testEmergencyCallbackModeChanged() throws Exception {
+        ArgumentCaptor<CarrierConfigManager.CarrierConfigChangeListener> callbackCaptor =
+                ArgumentCaptor.forClass(CarrierConfigManager.CarrierConfigChangeListener.class);
+
+        verify(mCarrierConfigManager).registerCarrierConfigChangeListener(any(),
+                callbackCaptor.capture());
+
+        CarrierConfigManager.CarrierConfigChangeListener callback = callbackCaptor.getValue();
+
+        assertNotNull(callback);
+
+        // ECBM supported
+        PersistableBundle b = getPersistableBundle(true);
+        doReturn(b).when(mCarrierConfigManager).getConfigForSubId(anyInt(), anyString());
+        callback.onCarrierConfigChanged(SLOT_0, SUB_1, 0, 0);
+
+        verify(mTelephonyManager).createForSubscriptionId(eq(SUB_1));
+
+        ArgumentCaptor<TelephonyCallback> telephonyCallbackCaptor =
+                ArgumentCaptor.forClass(TelephonyCallback.class);
+
+        // TelephonyCallback registered
+        verify(mTelephonyManager).registerTelephonyCallback(any(),
+                telephonyCallbackCaptor.capture());
+
+        TelephonyCallback telephonyCallback = telephonyCallbackCaptor.getValue();
+
+        assertNotNull(telephonyCallback);
+
+        // Carrier config changes, ECBM not supported
+        b = getPersistableBundle(false);
+        doReturn(b).when(mCarrierConfigManager).getConfigForSubId(anyInt(), anyString());
+        callback.onCarrierConfigChanged(SLOT_0, SUB_1, 0, 0);
+
+        // TelephonyCallback unregistered
+        verify(mTelephonyManager).unregisterTelephonyCallback(eq(telephonyCallback));
+    }
+
+    @Test
+    public void testEmergencyCallbackModeEnter() throws Exception {
+        ArgumentCaptor<CarrierConfigManager.CarrierConfigChangeListener> callbackCaptor =
+                ArgumentCaptor.forClass(CarrierConfigManager.CarrierConfigChangeListener.class);
+
+        verify(mCarrierConfigManager).registerCarrierConfigChangeListener(any(),
+                callbackCaptor.capture());
+
+        CarrierConfigManager.CarrierConfigChangeListener callback = callbackCaptor.getValue();
+
+        assertNotNull(callback);
+
+        // ECBM supported
+        PersistableBundle b = getPersistableBundle(true);
+        doReturn(b).when(mCarrierConfigManager).getConfigForSubId(anyInt(), anyString());
+        callback.onCarrierConfigChanged(SLOT_0, SUB_1, 0, 0);
+        callback.onCarrierConfigChanged(SLOT_1, SUB_2, 0, 0);
+
+        // Enter ECBM on slot 1
+        mContext.sendStickyBroadcast(getIntent(true, SLOT_1));
+
+        assertFalse(mEcbmHelper.isInEmergencyCallbackMode(SLOT_0));
+        assertTrue(mEcbmHelper.isInEmergencyCallbackMode(SLOT_1));
+    }
+
+    @Test
+    public void testEmergencyCallbackModeExit() throws Exception {
+        ArgumentCaptor<CarrierConfigManager.CarrierConfigChangeListener> callbackCaptor =
+                ArgumentCaptor.forClass(CarrierConfigManager.CarrierConfigChangeListener.class);
+
+        verify(mCarrierConfigManager).registerCarrierConfigChangeListener(any(),
+                callbackCaptor.capture());
+
+        CarrierConfigManager.CarrierConfigChangeListener callback = callbackCaptor.getValue();
+
+        assertNotNull(callback);
+
+        // ECBM supported
+        PersistableBundle b = getPersistableBundle(true);
+        doReturn(b).when(mCarrierConfigManager).getConfigForSubId(anyInt(), anyString());
+        callback.onCarrierConfigChanged(SLOT_0, SUB_1, 0, 0);
+
+        // Exit ECBM
+        mContext.sendStickyBroadcast(getIntent(false, SLOT_0));
+
+        assertFalse(mEcbmHelper.isInEmergencyCallbackMode(SLOT_0));
+    }
+
+    private static Intent getIntent(boolean inEcm, int slotIndex) {
+        Intent intent = new Intent(TelephonyManager.ACTION_EMERGENCY_CALLBACK_MODE_CHANGED);
+        intent.putExtra(TelephonyManager.EXTRA_PHONE_IN_ECM_STATE, inEcm);
+        intent.putExtra(SubscriptionManager.EXTRA_SLOT_INDEX, slotIndex);
+        return intent;
+    }
+
+    private static PersistableBundle getPersistableBundle(boolean supported) {
+        PersistableBundle bundle  = new PersistableBundle();
+        bundle.putBoolean(KEY_EMERGENCY_CALLBACK_MODE_SUPPORTED_BOOL, supported);
+        return bundle;
+    }
+
+    private static void logd(String str) {
+        Log.d(TAG, str);
+    }
+}
diff --git a/tests/src/com/android/services/telephony/domainselection/TelephonyDomainSelectionServiceTest.java b/tests/src/com/android/services/telephony/domainselection/TelephonyDomainSelectionServiceTest.java
index 0382d4b..d9c737e 100644
--- a/tests/src/com/android/services/telephony/domainselection/TelephonyDomainSelectionServiceTest.java
+++ b/tests/src/com/android/services/telephony/domainselection/TelephonyDomainSelectionServiceTest.java
@@ -82,7 +82,8 @@
                         @NonNull Looper looper, @NonNull ImsStateTracker imsStateTracker,
                         @NonNull DomainSelectorBase.DestroyListener listener,
                         @NonNull CrossSimRedialingController crossSimRedialingController,
-                        @NonNull CarrierConfigHelper carrierConfigHelper) {
+                        @NonNull CarrierConfigHelper carrierConfigHelper,
+                        @NonNull EmergencyCallbackModeHelper ecbmHelper) {
                     switch (selectorType) {
                         case DomainSelectionService.SELECTOR_TYPE_CALLING: // fallthrough
                         case DomainSelectionService.SELECTOR_TYPE_SMS: // fallthrough
@@ -105,8 +106,9 @@
         TestTelephonyDomainSelectionService(Context context,
                 @NonNull ImsStateTrackerFactory imsStateTrackerFactory,
                 @NonNull DomainSelectorFactory domainSelectorFactory,
-                @Nullable CarrierConfigHelper carrierConfigHelper) {
-            super(imsStateTrackerFactory, domainSelectorFactory, carrierConfigHelper);
+                @Nullable CarrierConfigHelper carrierConfigHelper,
+                @Nullable EmergencyCallbackModeHelper ecbmHelper) {
+            super(imsStateTrackerFactory, domainSelectorFactory, carrierConfigHelper, ecbmHelper);
             mContext = context;
         }
 
@@ -131,6 +133,7 @@
     @Mock private TransportSelectorCallback mSelectorCallback2;
     @Mock private ImsStateTracker mImsStateTracker;
     @Mock private CarrierConfigHelper mCarrierConfigHelper;
+    @Mock private EmergencyCallbackModeHelper mEcbmHelper;
 
     private final ServiceState mServiceState = new ServiceState();
     private final BarringInfo mBarringInfo = new BarringInfo();
@@ -152,7 +155,7 @@
 
         mContext = new TestContext();
         mDomainSelectionService = new TestTelephonyDomainSelectionService(mContext,
-                mImsStateTrackerFactory, mDomainSelectorFactory, mCarrierConfigHelper);
+                mImsStateTrackerFactory, mDomainSelectorFactory, mCarrierConfigHelper, mEcbmHelper);
         mDomainSelectionService.onCreate();
         mServiceHandler = new Handler(mDomainSelectionService.getLooper());
         mTestableLooper = new TestableLooper(mDomainSelectionService.getLooper());