Hi Own a 3 year old C8 2.0 HDi SX. My wife was cleaning it out today - getting ready to sell it. managed to trigger the alarm and then silenced it using the key fob. Helped by our youngest who enjoys operating the hazards, doors etc.. Left it for a couple of hours unlocked and when I went to start it this evening, display tells me it is in Economy Mode and the engine turns but will not fire - I am presuming the immobilisier is preventing start up. Anyone know whether this is a symptom of a security feature connected to the alarm being triggered - and if so can it be reset without involving dealers etc.. or does it sound like a fault? Cheers