very easy, the ecu will have very little connections to the 2 round plugs, I think tacho out, vehicle speed sensor, obd if it has anything, and immobiliser if it has anything.
compare the pin layout and wire number for each pin, ignore the ecu plug.
all you need is a multimeter and some way to label all the wires you have, and a notebook.
if you have an unlocked ecu, you can make it run with only 3 wires connected in those round plugs, switched live to power the double relay, fuel pump and starter motor.
double relay live comes from the alternator, engine loom has its own earth.
compare the pin layout and wire number for each pin, ignore the ecu plug.
all you need is a multimeter and some way to label all the wires you have, and a notebook.
if you have an unlocked ecu, you can make it run with only 3 wires connected in those round plugs, switched live to power the double relay, fuel pump and starter motor.
double relay live comes from the alternator, engine loom has its own earth.
need a part number? http://public.servicebox.peugeot.com/ and http://service.citroen.com/ will sort you out.