How to I change the Km to Miles on my Cadillac CTS 2003?

SOURCE: 2003 Cadillac CTS at 225,000 miles Code P0128

First off who ever said $400 to change a thermostat is trying to rip you off. The actual part is like $20 bucks max and its so easy to change. I can guide you through it if you would like.

The P0128 code is Coolant Thermostat Malfunction.

These are the possible causes for this code:
- Insufficient warm up time.
- Low engine coolant level.
- Leaking or stuck open thermostat.
- Malfunctioning engine coolant temperature sensor.

These are the possible quick fixes:
- Top OFF Engine Coolant
- Replaced Thermostat