GMC Repair: 2002 tracker, temperature guage, chevy tracker

Question
I own a 2002 Chevy Tracker.  Recently, the service engine soon light came on.  I had a diagnostic check on it and they told me it was the temperature guage is misreading the actual tempterature, but it really was not a big deal.  I have had two mechanics tell me they really would not worry about it if they were me.  However, I really do not want to live with the service engine light always on.  Is there a procedure to make it turn off permanently?  I have tried disconnecting the battery, but after a few weeks it always come back on.  It is a 2002 chevy tracker, 2.5 v6, 4wd, auto tranny.  Thanks a lot for your help. I really appreciate it.

Answer
Hi
OBD2 engine systems CANNOT have the service engine soon light by disconnecting the battery. They have to be cleared by a scanner.
If it is a P0128 code, The  proper fix is replacement of the thermostat.
I would want to fix it if it came into my shop....
I Hope this helps.
Good Luck
Pawl