We purchased a used Peugeot fleet car 16 months ago. It is a 2007 Peugeot 307 SE SW 1.6 petrol. It was first serviced by the dealer in October 2009. Until then it had performed perfectly. However, following that service we have started to get increasing numbers of warning indicators stating "Engine Management System Fault" while running, and the engine falls back to "limp-home" mode on reduced power. If we stop, switch off and then switch the ignition back on, the message disappears and the engine behaves normally again until the next fault message. The fault appears most commonly on motorway journeys, leaving us in a potentially dangerous situation with the immediate loss of power. On our last long motorway trip up to the Lakes (our main home is in Surrey) we suffered five such error messages. Following this, we checked the car into a local Peugeot garage. They were unable to find any log of the faults on the car's management system, but replaced part of the software, using the "YSC recall" version. They said that, almost certainly, that would cure the problem. However, on the return journey to Surrey, we had a further four occurrences of this warning. Apart from the inconvenience of having to stop repeatedly and re-set the system, it is potentially dangerous, especially in heavy, high speed traffic. We therefore need to get this sorted while the car is still under warranty (until August 2010). Could you tell us what is likely to be the real problem, and what our next move should be?