How do I fix code P0128?

To fix P0128, you may need to replace: thermostat, coolant temperature sensor. Low severity — generally safe to drive.

P0128: Coolant Temperature Below Thermostat Regulating Temperature

Common causes of P0128 include: Stuck-open thermostat, Faulty coolant temperature sensor.

The engine is running too cold — usually a stuck-open thermostat.

Common parts needed: thermostat, coolant temperature sensor.