Most of the time my phone (Nexus4,r19,stable) has  problems to
establish a connection with the Toyota Bluetooth Carkit.
I've attached my log files.

application-legacy-ubuntu-system-settings-.log
2015-05-22 12:23:03,460 - WARNING - file:///usr/lib/arm-linux-gnueabihf/qt5/qml/Ubuntu/Components/ListItems/SingleControl.qml:59:14: Unable to assign [undefined] to bool
UbuntuWindow - regular geometry
2015-05-22 12:23:03,840 - WARNING - UbuntuClipboard - Got invalid serialized mime data. Ignoring it.
2015-05-22 12:23:05,664 - WARNING - QQmlExpression: Expression file:///usr/share/ubuntu/settings/system/qml-plugins/bluetooth/PageComponent.qml:70:17 depends on non-NOTIFYable properties:
2015-05-22 12:23:05,665 - WARNING -     Bluetooth::agent
2015-05-22 12:23:05,792 - WARNING - file:///usr/share/ubuntu/settings/system/qml-plugins/bluetooth/PageComponent.qml:168:50: Unable to assign [undefined] to bool
2015-05-22 12:23:05,898 - WARNING - file:///usr/share/ubuntu/settings/system/qml-plugins/bluetooth/PageComponent.qml:168:50: Unable to assign [undefined] to bool
2015-05-22 12:23:09,248 - WARNING - Could not initiate service discovery: "Bad file descriptor"
2015-05-22 12:23:10,686 - WARNING - file:///usr/lib/arm-linux-gnueabihf/qt5/qml/Ubuntu/Components/PageWrapperUtils.js:30: TypeError: Cannot read property 'createObject' of null
2015-05-22 12:23:32,688 - WARNING - Error registering agent for the default adapter: QDBusError("org.bluez.Error.AlreadyExists", "Already Exists")
2015-05-22 12:23:32,855 - WARNING - QQmlExpression: Expression file:///usr/share/ubuntu/settings/system/qml-plugins/bluetooth/PageComponent.qml:70:17 depends on non-NOTIFYable properties:
2015-05-22 12:23:32,855 - WARNING -     Bluetooth::agent
2015-05-22 12:23:32,966 - WARNING - file:///usr/share/ubuntu/settings/system/qml-plugins/bluetooth/PageComponent.qml:168:50: Unable to assign [undefined] to bool
2015-05-22 12:23:33,046 - WARNING - file:///usr/share/ubuntu/settings/system/qml-plugins/bluetooth/PageComponent.qml:168:50: Unable to assign [undefined] to bool
2015-05-22 12:23:33,410 - WARNING - UbuntuClipboard - Got invalid serialized mime data. Ignoring it.
2015-05-22 12:23:42,687 - WARNING - Could not initiate service discovery: "Host is down"
2015-05-22 12:23:42,689 - WARNING - Could not initiate service discovery: "Connection refused"
2015-05-22 12:51:31,753 - WARNING - Error registering agent for the default adapter: QDBusError("org.bluez.Error.AlreadyExists", "Already Exists")
2015-05-22 12:51:31,754 - CRITICAL - Couldn't register agent at /com/canonical/SettingsBluetoothAgent/adapteragent
2015-05-22 12:51:31,934 - WARNING - QQmlExpression: Expression file:///usr/share/ubuntu/settings/system/qml-plugins/bluetooth/PageComponent.qml:70:17 depends on non-NOTIFYable properties:
2015-05-22 12:51:31,934 - WARNING -     Bluetooth::agent
2015-05-22 12:51:32,046 - WARNING - file:///usr/share/ubuntu/settings/system/qml-plugins/bluetooth/PageComponent.qml:168:50: Unable to assign [undefined] to bool
2015-05-22 12:51:32,209 - WARNING - file:///usr/lib/arm-linux-gnueabihf/qt5/qml/Ubuntu/Components/PageWrapperUtils.js:30: TypeError: Cannot read property 'createObject' of null
2015-05-22 12:51:32,363 - WARNING - file:///usr/share/ubuntu/settings/system/qml-plugins/bluetooth/PageComponent.qml:168:50: Unable to assign [undefined] to bool
2015-05-22 12:51:32,505 - WARNING - UbuntuClipboard - Got invalid serialized mime data. Ignoring it.
2015-05-22 13:53:25,425 - WARNING - QQmlExpression: Expression file:///usr/share/ubuntu/settings/system/qml-plugins/bluetooth/PageComponent.qml:70:17 depends on non-NOTIFYable properties:
2015-05-22 13:53:25,426 - WARNING -     Bluetooth::agent
2015-05-22 13:53:25,561 - WARNING - file:///usr/share/ubuntu/settings/system/qml-plugins/bluetooth/PageComponent.qml:168:50: Unable to assign [undefined] to bool
2015-05-22 13:53:25,561 - WARNING - file:///usr/lib/arm-linux-gnueabihf/qt5/qml/Ubuntu/Components/ListItems/SingleControl.qml:59:14: Unable to assign [undefined] to bool
UbuntuWindow - regular geometry
2015-05-22 13:53:26,035 - WARNING - UbuntuClipboard - Got invalid serialized mime data. Ignoring it.
2015-05-22 13:53:26,115 - WARNING - file:///usr/share/ubuntu/settings/system/qml-plugins/bluetooth/PageComponent.qml:168:50: Unable to assign [undefined] to bool