Re: injection computer replacing
a brand new "virgin" ecu will pair itself with your immob's codebox and perform the usual learing procedures by itself. however if you have a dry by wire accelerator (non-cable) then you may need to visit a dealer to have the throttle position sensor range learing procedure performed on the examiner smart machine, however even this is usually not neccessary if you leave the car idling for 5-10 mins before you touch the accelerator.
its very important that the new ecu is 100% brand new never been used even for a second. if it has been fitted previously it wont pair with your codebox and the immob will not switch off.