My M30 has (2) temp sensors in the thermostat housing. I am guessing one if coolant temp (the gauge) and one is for engine temp for the ECM. Do I have this correct? Also, if the temp sensor for the ECM is bad, would it throw a code? The mileage has dropped lately and the power is off when the engine is warm. I am wondering if I could be running in "cold engine" mode all of the time. The coolant temp gauge is straight up as always. Any thoughts???