While chasing my P0128 code which seems to show water temp coming up too slowly i wanted to change the engine coolant temp sensor on top of the engine. I have done the one on the rad but no joy. Rave says that the sensor should be connected to textbook to set it up. Does anyone know if the sensor actually requires some adjustment. Not sure why it can not be plug and play. I have read that that the trans stat can also cause this issue if it opens too soon. I do have a slightly cooler stat installed but had no codes for at least a year so I am doubting that my issue is the actual stat as it is a n.o.s. bmw stat. All insights appreciated and flames accepted.