Engine Light

Coolant level is not monitored by the Engine Computer but you check it in the overflow reservoir. There's "Min" and "Max" marks on it. The thermostat operation is not monitored either. If the heater gives nice hot air and the engine isn't overheating, the thermostat is working.

The fault code usually refers to the electrical wiring for the coolant temperature sensor. Check the connector to be sure the terminals aren't stretched or corroded. It is very rare for that sensor to fail on Chryslers. To find it, follow the upper radiator hose the where it connects on the engine. That's the thermostat housing. Two sensors will be near it. One will have one wire. You need to check the one with two wires.