Hello. When i turn on my vehicle my temp gauge rises normally but after engine its hot its position varies between normal running temp and any position between said position and maximum Hot temperature.

I've heard its the cluster circuit board at the back of it but how can i male sure of it?

I have a check engine light and gives me 2 codes. One is P150 that is bank 2 sensor 1 which i guess I have the upper left O2 sensor bad and needs to me replaces Correct me if I'm wrong.

The other one is P0125 which is for the Coolant temperature sensor. So having said that. Our truck are common to have a faulty temp gauge due to the cluster ecm. But is that my particular case ? Even if I got a code for a bad coolant temp sensor?

 

I'd disconnect the wire from the temp sensor. It'll be by the thermostat housing...the one with one wire going to it. Then start up the car and see if the gauge still moves on its own. If it moves around at all, I'd say it is the circuit board.

 

get a digital temp gun and see what readings you get over the rad and hoses