I own a T Reg. Fiat Duccato 1.9 Torbo Diesel and the Key Code light came on and even the AA could not fix it, so they towed me to a Fiat Main Dealer who did fix it and charged me £230.00. One month later it came on again and like before would not go out. In desperation and not wanting to pay out again I inspected nearly every wire and connection on the vehicle. I found a trip switch inside the Engine compartment right next to the Possative Connection of the battery. It is a round rubber encased switch and when pressed resets the key code light, to my great delight and relief.
Philg4649

Had same problem Adams Morey of southampton took the whole lot out don't have any immobiliser system now so no problems in the future except it might get nicked

Its the intertia switch used to stop engine in the event of a heavy impact. If we get a Ducato come into the dealership as a nonstart, the first thing we do is check it, usually with the AA guy still present, we always show the AA and customer where it is and how it is linked to the keycode system. If this is not the cause then quite often the pump unit can have problems due to water and vibration.

Hi,

Just a quick question, do the later Fiats etc have the inertia switch and is it in the same location? I have a 2.0 2003 model but I am sure everone else would find the location useful.

Regards
Stewart

Yep, on the bulkhead in the engine bay close to the positive battery terminal.

Cheers for the info, its always nice to be one step ahead of vehicle problems.
Regards
Stewart