diff --git a/obmc/mapper/server.py b/obmc/mapper/server.py
index 8817ae2..b49eeb0 100644
--- a/obmc/mapper/server.py
+++ b/obmc/mapper/server.py
@@ -267,6 +267,7 @@
             self.properties_changed_handler,
             dbus_interface=dbus.PROPERTIES_IFACE,
             signal_name='PropertiesChanged',
+            arg0=obmc.dbuslib.enums.OBMC_ASSOCIATIONS_IFACE,
             path_keyword='path',
             sender_keyword='sender')