On later models once the air-bag sytem has been activated the
prevents the engine from being started via the immobiliser. To over come this problem it is necessary to have the
system reprogrammed either by Renault or a garage that has the appropriate diagnostic equipment. For obvious safety and legal reasons many garages will not reprogramme second hand units.
Also remember to ensure your insurance is kept legit you would need to inform them of any changes or repairs.