It is designed to allow you to get home or to a garage rather than breaking down. The idea being the garage then plugs in a computer diagnostics and tells you exactly what's wrong, then repairs it and on you go. Only our experience is that our car has gone into limp home mode 40 times in six months (limp home mode is a power loss, as though someone has put a wedge of wood under the accelerator pedal so you can't get sufficient revs – if going even a gentle uphill it means speed can drop rapidly, yes this includes if on the outside lane of a busy motorway while overtaking a lorry. Very scary.) and the fault can't be found on our C Max. We've chucked £500 at three new parts based on Ford's guesswork. Now Ford is suggesting another repair that could cost £200-£900, but that still cannot guarantee it will fix it. Ford have been painful to deal with and show a total lack of regard for their customers, happy to send us off in a car that could cause a bad accident.