turbo diesel 1999 t reg engine key code ?

hi there i have just fitted a turbo diesel engine in to a non turbo van . i have swopped every thing ie loom, ecu, peddle . its all fitted correct but now the immobiliser light is flashing on the dashboard and the starter int getting power . that leads me to think its some thing to do with the key code . the question i ask is will it need the ecu coding in . many thanks david

david t
February 2010