Recently purchased a van and had an error light which shows up P23AD00 NOx sensor circuit range/ performance bank 1 sensor 3. I spoke to the previous owner who changed the nox sensor near then end of the exhaust line recently as he had this issue, which you can see is brand new. I have had it in the garage today and they are saying there is only 2 nox sensors found and are confused with the error. Standard Google search is saying it is an exhaust gas temp sensor, he is saying the nox sensor readings are low 90ppm on the first point and 30ppm after. Is the error correct or has anyone had this issue before, thankyou.