diff --git a/include/NetworkManager.h b/include/NetworkManager.h
index bb67b8f7a5..e0194b6462 100644
--- a/include/NetworkManager.h
+++ b/include/NetworkManager.h
@@ -492,6 +492,9 @@ typedef enum {
 	/* Problem with the RFC 2684 Ethernet over ADSL bridge */
 	NM_DEVICE_STATE_REASON_BR2684_FAILED = 51,
 
+	/* ModemManager not running */
+	NM_DEVICE_STATE_REASON_MODEM_MANAGER_UNAVAILABLE = 52,
+
 	/* Unused */
 	NM_DEVICE_STATE_REASON_LAST = 0xFFFF
 } NMDeviceStateReason;
diff --git a/introspection/nm-device.xml b/introspection/nm-device.xml
index 5b2c98b3c6..240cbd3147 100644
--- a/introspection/nm-device.xml
+++ b/introspection/nm-device.xml
@@ -559,6 +559,11 @@
           Problem with the RFC 2684 Ethernet over ADSL bridge.
         </tp:docstring>
       </tp:enumvalue>
+      <tp:enumvalue suffix="MODEM_MANAGER_UNAVAILABLE" value="52">
+        <tp:docstring>
+          ModemManager was not running or quit unexpectedly.
+        </tp:docstring>
+      </tp:enumvalue>
     </tp:enum>
 
     <tp:struct name="NM_DEVICE_STATE_REASON_STRUCT">
diff --git a/src/nm-device.c b/src/nm-device.c
index 18aa92a96a..23e8ed41ab 100644
--- a/src/nm-device.c
+++ b/src/nm-device.c
@@ -4520,6 +4520,8 @@ reason_to_string (NMDeviceStateReason reason)
 		return "dependency-failed";
 	case NM_DEVICE_STATE_REASON_BR2684_FAILED:
 		return "br2684-bridge-failed";
+	case NM_DEVICE_STATE_REASON_MODEM_MANAGER_UNAVAILABLE:
+		return "modem-manager-unavailable";
 	default:
 		break;
 	}