Trouble code 128 no code repair shown.

Use your scanner to view live data and see what the coolant temperature is. If it stays below about 180 degrees, replace the thermostat. This code will not turn the Check Engine light on so it could be the equivalent of code 17 on pre-OBD2 cars from '95 and older. That code was "running cold too long". Every Chrysler product had that code up here in snow country because it took longer than six minutes to reach operating temperature. That code erased automatically after 50 engine starts when the weather warmed up.

Also, this code is not what will be set when there's an electrical problem with the temperature sensor or its wiring. This code says the Engine Computer is getting a proper reading from the sensor but is not happy with that reading. Besides not turning the Check Engine light on, if you erase it, you should see that if it sets again, it will not do that right away. If the engine is warm already, the code may not set again until it has cooled down overnight.