It reads like t-stat is working as it should
Heater hose should warm up with the engine.
Upper rad hose should not.
Upper rad hose should only start warming up IF coolant behind t-stat gets above 190degF, on cold days that may not happen, and even then t-stat may only open slightly, cold coolant coming in from lower rad will cause t-stat to close again.
So t-stat will open and close to maintain the minimum 190degF for proper engine operation temp.
Upper rad hose just reflects this opening and closing.
There are 2 ECT sensors, well one sensor and one sender.
The sender is for the dash board temp gauge, it has 1 wire, and that's the one you tested.
You said you changed the ECT sensor, this is the 2 wire device that looks similar to the sender.
The ECT sensor is only used by the computer, and this is what computer uses to "see" coolant temp.
And this is what would set your code if it's wiring or the sensor itself had a problem.
The computer sends this sensor 5 volts DC, the sensor is a variable resistor so sends a lower voltage back to computer, this lower voltage "tells" the computer the temp of the sensor/coolant.
Last edited by RonD; 03-09-2014 at 02:01 PM.