peugeot 406 hdi - engine management light - plainspug

engine management light stays on at all times and car is not in limp mode it ,s got plenty of power and revs way over 3000rpm. just bought car and after 30 miles light came on now someone has told me that if car at sometime had cherry in it that it may have damaged pump causing problem. only thing i see on dash says electronic ignition fault. if you have any solution to this your help would be appreciated.