On my 02 Audi Quattro 1.8T, how do I check if my map controlled thermostat is bad? What should the electrical reading be at the terminal and what should the reading be at the thermostat itself? I got a P1726 code that says the coolant temperature sensor. I replace the sensor but I still get the code. My temperature gauge will read almost zero when the car is running at spedd and will go halfway after I am idling for a while on stop lights. It will drop to almost zero again when I go. I know it is the thermostat on conventional cars, but the dealership said that it is an electronic thermostat and not serviceable. Is the ECM reading a resistance value in the thermostat and report that to the computer, or is the computer sending it a signal to open or close based on the coolant sensor? I might replace the thermostat and then finding out that it is not the problem and it was the ECM not giving it the right signal. Please help in diagnosing this because the Audi electronic manual is not a big help.