Did some digging about this code. When I dumped the freeze frame data on my scan tool, it showed the "ECT 1" at 159 degrees F, engine coolant sensor 1 close to the thermostat. When I checked the service manual, it indicates that coolant temp must be above 158 degrees F. That 158 number appears in the service manual as minimum temp for the test to operate correctly. With engine warmed up, 20 mile drive and ambient temp about 65 F, I used an IR temp gauge and looked at the sensor and surrounding metal and thermostat housing, I only see about 140 degrees F. Temp gauge on dash runs below the half way point. Could I be seeing the symptoms of a marginally cool running engine? I would think that the base of ECT 1 should show something close to engine coolant temp. Thermostat should start to open at 169 to 176 degrees F and fully open at 194 degrees F. Thermostats are cheaper than CC.