A code P0125 may mean that one or more of the following has happened: Insufficient warm up time
Low engine coolant level
Leaking or stuck open thermostat
Faulty coolant temperature sensor
Possible SolutionsThe simplest thing to do is to reset the code and see if it comes back.
If the code comes back, the problem is likely going to be the result of the above causes (faulty thermostat, faulty coolant sensor, or a low coolant level).