key code light fiat punto mk2?

hi folks was hoping you guys could maybe shed some light on my problem. i have a 2001 fiat punto mia mk2 which i have replaced the engine. i have used all the original electrics ie,cam sensor,intake manifold and ecu from my original engine. the only thing i have chaned is the block and head. even used my original gearbox, with a new clutch. now when i try to start her my ignition lights are coming on no problem but my code light is staying on permanantly. i have no red key as believe my model did not require one and have no code card. but as code light is not flashing do not think the emergency start up procedure would be much help. have checked all the earth points to make sure they were good and have replaced the battery but still no luck. any possible suggestions would be welcome as apart from taking to fiat for megabucks dont know what to try next. hopefully you guys can help and thanks for takin the time to read this.