What does it mean when coolant temperature is below thermostat regulating temperature?

It means that the ECM/PCM has “noticed” that the engine coolant temperature is consistently running below thermostat regulating temperature. In other words, the engine is running cooler than it should. To put it another way, the engine is running too cool or the temperature does not increase quickly enough.

How do I fix the engine code P0128?

What repairs can fix the P0128 code?

  1. Replacing the thermostat (most common repair)
  2. Replacing the coolant temperature sensor, or the wiring and connector associated with the sensor being damaged.

What happens when thermostat is stuck open?

Thermostat stuck open: When the thermostat is stuck open, the engine temperature drops below normal when driving, especially on the highway in cold weather. A stuck-open thermostat can also cause lack of heat from the heating system. The Check Engine light may come on too.

How do you fix low coolant temp?

If you don’t feel safe driving, have your car towed to the nearest shop. These repairs typically require the mechanic draining the coolant, and replacing the defective component, being either the water hose or the radiator. The mechanic will then refill the coolant to fix the low coolant level.

Is it bad to drive with thermostat stuck open?

If you are driving your vehicle and the thermostat is stuck in the open position, it’s definitely going to cause some problems for you. When your thermostat is unable to properly close when it needs to, the flow of coolant will be unrestricted throughout your engine.

What is the code for coolant below thermostat?

OBD-II Trouble Codes P0128 Code: Coolant Temperature Below Thermostat Regulating Temperature

What does it mean when your coolant is not at the optimum temperature?

When the coolant does not reach the optimum temperature, it can cause poor engine performance and bad fuel economy. Since this often indicates a problem with the thermostat, regardless if you are driving a Dodge, a Ford, or a Jeep, the P0128 code is likely to appear once your coolant thermostat or temperature sensor fails.

What should coolant temp be before radiator fan engages?

The radiator cooling fan on some vehicles doesn’t even engage until after the coolant reaches nearly 230 degrees. So if the engine is expecting 200-230°F (most thermostats open at just under 200°F) but the ECM only sees 170°F, well, you can see why the ECM/PCM algorithm would store the code and illuminate the MIL.

What does it mean when your thermostat says p0128?

Also referred as “Thermostat Below Regulating Threshold”, Error Code P0128 means the PCM (Powertrain Control Module) of the vehicle has detected a problem on the thermostat, as it failed to reach the required temperature level within the specified time after starting the engine.