diff --git a/packages/CarSystemUI/src/com/android/systemui/car/navigationbar/SystemBarConfigs.java b/packages/CarSystemUI/src/com/android/systemui/car/navigationbar/SystemBarConfigs.java
index e316139326a90..078196e18b886 100644
--- a/packages/CarSystemUI/src/com/android/systemui/car/navigationbar/SystemBarConfigs.java
+++ b/packages/CarSystemUI/src/com/android/systemui/car/navigationbar/SystemBarConfigs.java
@@ -305,14 +305,14 @@ public class SystemBarConfigs {
             e.printStackTrace();
         }
 
-        if (!mTopNavBarEnabled && notificationPanelMediatorUsed.isAssignableFrom(
-                TopNotificationPanelViewMediator.class)) {
+        if (!mTopNavBarEnabled && TopNotificationPanelViewMediator.class.isAssignableFrom(
+                notificationPanelMediatorUsed)) {
             throw new RuntimeException(
                     "Top System Bar must be enabled to use " + notificationPanelMediatorName);
         }
 
-        if (!mBottomNavBarEnabled && notificationPanelMediatorUsed.isAssignableFrom(
-                BottomNotificationPanelViewMediator.class)) {
+        if (!mBottomNavBarEnabled && BottomNotificationPanelViewMediator.class.isAssignableFrom(
+                notificationPanelMediatorUsed)) {
             throw new RuntimeException("Bottom System Bar must be enabled to use "
                     + notificationPanelMediatorName);
         }
diff --git a/packages/CarSystemUI/tests/src/com/android/systemui/car/navigationbar/SystemBarConfigsTest.java b/packages/CarSystemUI/tests/src/com/android/systemui/car/navigationbar/SystemBarConfigsTest.java
index 7eb41de82ae03..0c62f8b4a22b7 100644
--- a/packages/CarSystemUI/tests/src/com/android/systemui/car/navigationbar/SystemBarConfigsTest.java
+++ b/packages/CarSystemUI/tests/src/com/android/systemui/car/navigationbar/SystemBarConfigsTest.java
@@ -33,7 +33,14 @@ import androidx.test.filters.SmallTest;
 
 import com.android.systemui.R;
 import com.android.systemui.SysuiTestCase;
+import com.android.systemui.broadcast.BroadcastDispatcher;
+import com.android.systemui.car.CarDeviceProvisionedController;
 import com.android.systemui.car.CarSystemUiTest;
+import com.android.systemui.car.notification.NotificationPanelViewController;
+import com.android.systemui.car.notification.NotificationPanelViewMediator;
+import com.android.systemui.car.notification.PowerManagerHelper;
+import com.android.systemui.car.notification.TopNotificationPanelViewMediator;
+import com.android.systemui.statusbar.policy.ConfigurationController;
 
 import org.junit.Before;
 import org.junit.Test;
@@ -55,8 +62,6 @@ public class SystemBarConfigsTest extends SysuiTestCase {
     private SystemBarConfigs mSystemBarConfigs;
     @Mock
     private Resources mResources;
-    @Mock
-    private CarNavigationBarView mCarNavigationBarView;
 
     @Before
     public void setUp() {
@@ -108,6 +113,33 @@ public class SystemBarConfigsTest extends SysuiTestCase {
         mSystemBarConfigs = new SystemBarConfigs(mResources);
     }
 
+    @Test
+    public void onInit_topNotifPanelViewMediatorUsed_topBarEnabled_doesNotThrowException() {
+        when(mResources.getBoolean(R.bool.config_enableTopNavigationBar)).thenReturn(true);
+        when(mResources.getString(R.string.config_notificationPanelViewMediator)).thenReturn(
+                TestTopNotificationPanelViewMediator.class.getName());
+
+        mSystemBarConfigs = new SystemBarConfigs(mResources);
+    }
+
+    @Test(expected = RuntimeException.class)
+    public void onInit_topNotifPanelViewMediatorUsed_topBarNotEnabled_throwsRuntimeException() {
+        when(mResources.getBoolean(R.bool.config_enableTopNavigationBar)).thenReturn(false);
+        when(mResources.getString(R.string.config_notificationPanelViewMediator)).thenReturn(
+                TestTopNotificationPanelViewMediator.class.getName());
+
+        mSystemBarConfigs = new SystemBarConfigs(mResources);
+    }
+
+    @Test
+    public void onInit_notificationPanelViewMediatorUsed_topBarNotEnabled_doesNotThrowException() {
+        when(mResources.getBoolean(R.bool.config_enableTopNavigationBar)).thenReturn(false);
+        when(mResources.getString(R.string.config_notificationPanelViewMediator)).thenReturn(
+                NotificationPanelViewMediator.class.getName());
+
+        mSystemBarConfigs = new SystemBarConfigs(mResources);
+    }
+
     @Test
     public void getTopSystemBarLayoutParams_topBarEnabled_returnsTopSystemBarLayoutParams() {
         mSystemBarConfigs = new SystemBarConfigs(mResources);
@@ -239,4 +271,20 @@ public class SystemBarConfigsTest extends SysuiTestCase {
         when(mResources.getBoolean(R.bool.config_hideRightSystemBarForKeyboard)).thenReturn(
                 false);
     }
+
+    // Intentionally using a subclass of TopNotificationPanelViewMediator for testing purposes to
+    // ensure that OEM's will be able to implement and use their own NotificationPanelViewMediator.
+    private class TestTopNotificationPanelViewMediator extends
+            TopNotificationPanelViewMediator {
+        TestTopNotificationPanelViewMediator(
+                CarNavigationBarController carNavigationBarController,
+                NotificationPanelViewController notificationPanelViewController,
+                PowerManagerHelper powerManagerHelper,
+                BroadcastDispatcher broadcastDispatcher,
+                CarDeviceProvisionedController carDeviceProvisionedController,
+                ConfigurationController configurationController) {
+            super(carNavigationBarController, notificationPanelViewController, powerManagerHelper,
+                    broadcastDispatcher, carDeviceProvisionedController, configurationController);
+        }
+    }
 }