Hello,
This DTC is not a problem with your vehicle's thermostat. If anything it is a problem with your vehicle's Engine Coolant Temperature Sensor [ECT]. In the diagrams down below I have included the vehicle manufacturers diagnostic troubleshooting flowchart for DTC P0128. Please go through this guide and get back to us with what you find out.
Thanks,
Alex
2CarPros
Images (Click to make bigger)
SPONSORED LINKS
Tuesday, October 8th, 2019 AT 10:41 PM