diff --git a/telecomm/java/android/telecom/CallDiagnosticService.java b/telecomm/java/android/telecom/CallDiagnosticService.java
index 201c5db..a5f7729 100644
--- a/telecomm/java/android/telecom/CallDiagnosticService.java
+++ b/telecomm/java/android/telecom/CallDiagnosticService.java
@@ -24,6 +24,8 @@
 import android.content.Intent;
 import android.os.IBinder;
 import android.os.RemoteException;
+import android.telephony.Annotation;
+import android.telephony.ims.ImsReasonInfo;
 import android.util.ArrayMap;
 
 import com.android.internal.telecom.ICallDiagnosticService;
@@ -96,6 +98,12 @@
                 throws RemoteException {
             handleBluetoothCallQualityReport(qualityReport);
         }
+
+        @Override
+        public void notifyCallDisconnected(@NonNull String callId,
+                @NonNull DisconnectCause disconnectCause) throws RemoteException {
+            handleCallDisconnected(callId, disconnectCause);
+        }
     }
 
     /**
@@ -257,6 +265,32 @@
     }
 
     /**
+     * Handles a request from the Telecom framework to get a disconnect message from the
+     * {@link CallDiagnosticService}.
+     * @param callId The ID of the call.
+     * @param disconnectCause The telecom disconnect cause.
+     */
+    private void handleCallDisconnected(@NonNull String callId,
+            @NonNull DisconnectCause disconnectCause) {
+        Log.i(this, "handleCallDisconnected: call=%s; cause=%s", callId, disconnectCause);
+        DiagnosticCall diagnosticCall = mDiagnosticCallByTelecomCallId.get(callId);
+        CharSequence message;
+        if (disconnectCause.getImsReasonInfo() != null) {
+            message = diagnosticCall.onCallDisconnected(disconnectCause.getImsReasonInfo());
+        } else {
+            message = diagnosticCall.onCallDisconnected(
+                    disconnectCause.getTelephonyDisconnectCause(),
+                    disconnectCause.getTelephonyPreciseDisconnectCause());
+        }
+        try {
+            mAdapter.overrideDisconnectMessage(callId, message);
+        } catch (RemoteException e) {
+            Log.w(this, "handleCallDisconnected: call=%s; cause=%s; %s",
+                    callId, disconnectCause, e);
+        }
+    }
+
+    /**
      * Handles an incoming bluetooth call quality report from Telecom.  Notifies via
      * {@link CallDiagnosticService#onBluetoothCallQualityReportReceived(
      * BluetoothCallQualityReport)}.
diff --git a/telecomm/java/android/telecom/DisconnectCause.java b/telecomm/java/android/telecom/DisconnectCause.java
index 1472a4a..ed7b79f 100644
--- a/telecomm/java/android/telecom/DisconnectCause.java
+++ b/telecomm/java/android/telecom/DisconnectCause.java
@@ -16,9 +16,13 @@
 
 package android.telecom;
 
+import android.annotation.Nullable;
 import android.media.ToneGenerator;
 import android.os.Parcel;
 import android.os.Parcelable;
+import android.telephony.Annotation;
+import android.telephony.PreciseDisconnectCause;
+import android.telephony.ims.ImsReasonInfo;
 import android.text.TextUtils;
 
 import java.util.Objects;
@@ -112,6 +116,9 @@
     private CharSequence mDisconnectDescription;
     private String mDisconnectReason;
     private int mToneToPlay;
+    private int mTelephonyDisconnectCause;
+    private int mTelephonyPreciseDisconnectCause;
+    private ImsReasonInfo mImsReasonInfo;
 
     /**
      * Creates a new DisconnectCause.
@@ -155,11 +162,36 @@
      */
     public DisconnectCause(int code, CharSequence label, CharSequence description, String reason,
             int toneToPlay) {
+        this(code, label, description, reason, toneToPlay,
+                android.telephony.DisconnectCause.ERROR_UNSPECIFIED,
+                PreciseDisconnectCause.ERROR_UNSPECIFIED,
+                null /* imsReasonInfo */);
+    }
+
+    /**
+     * Creates a new DisconnectCause instance.
+     * @param code The code for the disconnect cause.
+     * @param label The localized label to show to the user to explain the disconnect.
+     * @param description The localized description to show to the user to explain the disconnect.
+     * @param reason The reason for the disconnect.
+     * @param toneToPlay The tone to play on disconnect, as defined in {@link ToneGenerator}.
+     * @param telephonyDisconnectCause The Telephony disconnect cause.
+     * @param telephonyPreciseDisconnectCause The Telephony precise disconnect cause.
+     * @param imsReasonInfo The relevant {@link ImsReasonInfo}, or {@code null} if not available.
+     * @hide
+     */
+    public DisconnectCause(int code, CharSequence label, CharSequence description, String reason,
+            int toneToPlay, @Annotation.DisconnectCauses int telephonyDisconnectCause,
+            @Annotation.PreciseDisconnectCauses int telephonyPreciseDisconnectCause,
+            @Nullable ImsReasonInfo imsReasonInfo) {
         mDisconnectCode = code;
         mDisconnectLabel = label;
         mDisconnectDescription = description;
         mDisconnectReason = reason;
         mToneToPlay = toneToPlay;
+        mTelephonyDisconnectCause = telephonyDisconnectCause;
+        mTelephonyPreciseDisconnectCause = telephonyPreciseDisconnectCause;
+        mImsReasonInfo = imsReasonInfo;
     }
 
     /**
@@ -209,6 +241,33 @@
     }
 
     /**
+     * Returns the telephony {@link android.telephony.DisconnectCause} for the call.
+     * @return The disconnect cause.
+     * @hide
+     */
+    public @Annotation.DisconnectCauses int getTelephonyDisconnectCause() {
+        return mTelephonyDisconnectCause;
+    }
+
+    /**
+     * Returns the telephony {@link android.telephony.PreciseDisconnectCause} for the call.
+     * @return The precise disconnect cause.
+     * @hide
+     */
+    public @Annotation.PreciseDisconnectCauses int getTelephonyPreciseDisconnectCause() {
+        return mTelephonyPreciseDisconnectCause;
+    }
+
+    /**
+     * Returns the telephony {@link ImsReasonInfo} associated with the call disconnection.
+     * @return The {@link ImsReasonInfo} or {@code null} if not known.
+     * @hide
+     */
+    public @Nullable ImsReasonInfo getImsReasonInfo() {
+        return mImsReasonInfo;
+    }
+
+    /**
      * Returns the tone to play when disconnected.
      *
      * @return the tone as defined in {@link ToneGenerator} to play when disconnected.
@@ -217,7 +276,8 @@
         return mToneToPlay;
     }
 
-    public static final @android.annotation.NonNull Creator<DisconnectCause> CREATOR = new Creator<DisconnectCause>() {
+    public static final @android.annotation.NonNull Creator<DisconnectCause> CREATOR
+            = new Creator<DisconnectCause>() {
         @Override
         public DisconnectCause createFromParcel(Parcel source) {
             int code = source.readInt();
@@ -225,7 +285,11 @@
             CharSequence description = TextUtils.CHAR_SEQUENCE_CREATOR.createFromParcel(source);
             String reason = source.readString();
             int tone = source.readInt();
-            return new DisconnectCause(code, label, description, reason, tone);
+            int telephonyDisconnectCause = source.readInt();
+            int telephonyPreciseDisconnectCause = source.readInt();
+            ImsReasonInfo imsReasonInfo = source.readParcelable(null);
+            return new DisconnectCause(code, label, description, reason, tone,
+                    telephonyDisconnectCause, telephonyPreciseDisconnectCause, imsReasonInfo);
         }
 
         @Override
@@ -241,6 +305,9 @@
         TextUtils.writeToParcel(mDisconnectDescription, destination, flags);
         destination.writeString(mDisconnectReason);
         destination.writeInt(mToneToPlay);
+        destination.writeInt(mTelephonyDisconnectCause);
+        destination.writeInt(mTelephonyPreciseDisconnectCause);
+        destination.writeParcelable(mImsReasonInfo, 0);
     }
 
     @Override
@@ -254,7 +321,10 @@
                 + Objects.hashCode(mDisconnectLabel)
                 + Objects.hashCode(mDisconnectDescription)
                 + Objects.hashCode(mDisconnectReason)
-                + Objects.hashCode(mToneToPlay);
+                + Objects.hashCode(mToneToPlay)
+                + Objects.hashCode(mTelephonyDisconnectCause)
+                + Objects.hashCode(mTelephonyPreciseDisconnectCause)
+                + Objects.hashCode(mImsReasonInfo);
     }
 
     @Override
@@ -265,7 +335,11 @@
                     && Objects.equals(mDisconnectLabel, d.getLabel())
                     && Objects.equals(mDisconnectDescription, d.getDescription())
                     && Objects.equals(mDisconnectReason, d.getReason())
-                    && Objects.equals(mToneToPlay, d.getTone());
+                    && Objects.equals(mToneToPlay, d.getTone())
+                    && Objects.equals(mTelephonyDisconnectCause, d.getTelephonyDisconnectCause())
+                    && Objects.equals(mTelephonyPreciseDisconnectCause,
+                    d.getTelephonyPreciseDisconnectCause())
+                    && Objects.equals(mImsReasonInfo, d.getImsReasonInfo());
         }
         return false;
     }
@@ -325,6 +399,11 @@
                 + " Label: (" + label + ")"
                 + " Description: (" + description + ")"
                 + " Reason: (" + reason + ")"
-                + " Tone: (" + mToneToPlay + ") ]";
+                + " Tone: (" + mToneToPlay + ") "
+                + " TelephonyCause: " + mTelephonyDisconnectCause + "/"
+                + mTelephonyPreciseDisconnectCause
+                + " ImsReasonInfo: "
+                + mImsReasonInfo
+                + "]";
     }
 }
diff --git a/telecomm/java/com/android/internal/telecom/ICallDiagnosticService.aidl b/telecomm/java/com/android/internal/telecom/ICallDiagnosticService.aidl
index 65b4d19..fc9879a 100644
--- a/telecomm/java/com/android/internal/telecom/ICallDiagnosticService.aidl
+++ b/telecomm/java/com/android/internal/telecom/ICallDiagnosticService.aidl
@@ -18,6 +18,7 @@
 
 import android.telecom.BluetoothCallQualityReport;
 import android.telecom.CallAudioState;
+import android.telecom.DisconnectCause;
 import android.telecom.ParcelableCall;
 import com.android.internal.telecom.ICallDiagnosticServiceAdapter;
 
@@ -34,4 +35,5 @@
     void removeDiagnosticCall(in String callId);
     void receiveDeviceToDeviceMessage(in String callId, int message, int value);
     void receiveBluetoothCallQualityReport(in BluetoothCallQualityReport qualityReport);
+    void notifyCallDisconnected(in String callId, in DisconnectCause disconnectCause);
 }