After driving and after engine off,the gauge of my temperature meter does'nt go back to the lowest position,it just in the 1/4 position,sometimes 1/8 position. Hence, upon starting my car and upon reaching its optimum operation temperature the gauge almost in the overheating position but it was not overheating. Sometimes it goes on the lowest position upon engine off but rarely happens. What i did when it doesnt go back to its lowest position upon engine off is that i disconnect the neagtive battery terminal and reconnect it after 2 minutes and the gauge went to the lowest position. What is the problem of my car? Is the cluster panel malfunctioning or the ECT sensor and thermostat faulty?

I canceled engine light several times but it keeps coming back, I changed diesel pump sensors and no solution.

Check light keep coming up after I've changed the MAP sensor

It won't start until I remove common rail pressure sensor