I lost my keys for my ducato 100 multijet (ford engine) and was quoted to death to have locks changed/re-coded ecu.(as keys were lost near home).
So I went for the option of replacing with used parts from a van breaker.
I had to replace ignition/ecu/fusebox all works fine now plip opening starts
etc but the fuel gauge does not work and the warning lamp flash`s constantly, any ideas chaps does it need a ecu reset (I`m stumped)
the only other fault I can guess at is a friend attempted in vain to open van by tripping central locking by reverse powering certain feeds (indicaters reverse gearbox switch) etc could this have done any harm (but take into account I replaced all parts after I got into vehicle.

Possibly a fuse, if you haven't already checked, or perhaps an electrical block that's been missed when fitting the replacement parts.

I've found a wiring diagram which shows the system, I hope it's of help.

Couldn't find a key, but I figure that it's something like this.

CAOO - Ignition
B511 - ECU
1211 - Tank sender unit and pump assembly
0004 - Dash gauges / Fuel gauge

On the older model there was a proxy alignment procedure to align fuel gauge and synchronize bsi , ecu. Not sure if its supported on multiecu scan for the 2.2 though.

Disconect the red cable(s) from body computer (dash left)
to unpower it for one minute