Why is my 2004 Lincoln temperature gague reading hot? on 2004 Lincoln Town Car

My 2004 Lincoln town car is not running hot but the temperature gauge is reading hot. I replaced the thermostat and the cylinder thermostat sensor but it is still reading hot. i had codes p1299 and p1290 can you please help me?

Asked by for the 2004 Lincoln Town Car
try cooling temp sensor for the coolant temp gauge