My 406 doesnt have a keypad immobiliser, the pump came from a 97 406 so i dont know if that makes a difference? The original pump keeps over advancing the fuel despite being mechanically adjusted they think that there is an internal fault in it its a bosch pump I dont know if that helps :)

Have they replaced it with a Bosch pump, only the lucas pump has a different output configuration so you need to change the injector pipes as well. Is there a single terminal with a wire connected to it, just above where the injector pipes are fitted? I'm not sure what type of pump is fitted to the 1.9 but I wouldn't have thought it was programmed. Is the replacement pump identical to the original?

Its suprised me when the mechanic told me. I will have a look at the wiring tomorrow and see if it is a single terminal. They have swapped the bosch pump like for like, I will get the part number from the mechanic. I was originally told it was a mechanical pump so i cant understand why there is a programming problem. Have you any idea how much it would cost to get the original pump reconditioned just in case i have to go down that route. Thank you for information i really appreciate it :) this is becoming frustrating as there is nothing else wrong with the car

Robin thinks its chipped, your mechanic thinks its mechanical, all the XUD engines I have had experience with have had purely mechanical pumps, but having said that yours will be post '96 when they did include some electronic control. Does one of your injectors have a wire connected to it? If so it is partially electronic but I don't think its coded, unless its to do with the immobiliser system.