Toyota Repair: help, diesel engines, toyota dealer

Question
i have a 2003 Toyota Adventist diesel d cat which is excessively smoking due to the 5th injector as it injecting all the time had injector removed and tested and told that it is ok i also have constant electrical feed to the injector when injector is disconnected it goes into limp mode is there anything you could help me with as not sure where to go from here Toyota dealer couldn't help me with this hope to hear from you soon thankyou

Answer
I don't have much information on diesel engines as they are not sold in the US, I assume that it works something like a gas engine, the injectors will have constant voltage to one side and the other side is grounded off/on by the computer, if the injector stays open it would mean that it's grounded all the time through either the computer or a short circuit to ground somewhere between the injector and the computer.