How do I fix the code p0118?

Question

I have a Hyundai new accent 2008 car, 1.6 l, 4cyl, fwd, manual 1.6l,135000 km ,               
Because of overheating before, an over hole maintenance was taken and due to a little deformation in cylinder head, 2 head gasket are  installed to compensate the cylinder head thickness after resurface it
The cooling system have 2 indicator lamps one blue for low temp. and the other red for high temp. after some weeks i found the red lamp on in traffic but didn’t in highways
By checking the cooling system
•    Replacing thermostat, temperature sensor, radiator cap,
•    Cleaning radiator (aluminum type) internally and externally, checking the coolant level regularly is detect no leaks
•    Checking the electric fans operation are ok.
•    Checking water pump impeller is ok.
•    Checking by using another controller
•    Checking by using instrument cluster and indicator lights panel controller
•    Checking bad gasket and cracked head using block tester and test fluid it found ok.
-circuits is checked and it's ok
After that i found the same state red lamp on in traffic but didn’t in highways
Using scan tool which indicate that red lamp is on at 94-96 degree c and radiator fan on at 96-98 degree c and code p0118 ( mean engine coolant temp. circuit high input) so what is the reason for red lamp on at the engine normal temp.?

Answer 1

P0118 Engine coolant temperature circuit voltage high

With this code the signal connection is faulty , that or poor connection with the ECT sensor,