Issues with the temperature gauge

[Evholic_1]

Hello! The temperature gauge on my Corsa stops reading on the dashboard, and the cooling fan comes on. The code I read is P0128. If I turn it off, the fan turns off and the temperature gauge doesn't keep a constant temperature. It fluctuates between 70-90. Even though I changed everything I had to change, the problem is still there. Any thoughts?

 

[rx7junkie]

How is it now? Did you try changing the thermostat?

 

[Hipman]

It sounds like a thermostat issue, even if you've replaced parts. The P0128 code typically indicates a thermostat that's stuck open. It might need replacement.