There is a possibility that the reading from the EGR valve, coming from the sensor, is telling the computer that the valve is open, whether is is or not. If the problem, for example, is the result of the voltage to the sensor being missing, the resulting low reading could be due to the computer having its own issues. This is a good example of jumping to conclusions leading to erroneous parts changing. I have seen the problem simply being the result of incorrect programming and a reflash fixed the problem. Ray