P0128 is a generic OBD-II trouble code that means: Coolant Thermostat – Coolant Temperature Below Regulating Temperature. Usually yes in the short term. The car normally runs fine, but fix it soon to avoid failing an emissions test or causing further problems.
What does P0128 mean?
P0128 is a generic OBD-II trouble code that means: Coolant Thermostat – Coolant Temperature Below Regulating Temperature. The engine control module (ECM) stores this code when it detects a fault related to: Coolant Thermostat.
Can I still drive?
Usually yes in the short term. The car normally runs fine, but fix it soon to avoid failing an emissions test or causing further problems.
Symptoms
- Check engine light is on
- Higher fuel consumption
- Often no noticeable drivability symptoms
Common causes
- Thermostat stuck open or closed
- Low coolant level or a cooling system fault
- Faulty sensor or component
How to fix it
- Read all stored codes and freeze-frame data with an OBD-II scanner
- Check the coolant level and look for leaks
- Replace the thermostat and bleed the cooling system
- Clear the code and road-test the car to confirm the repair
Frequently asked questions
What does code P0128 mean?
P0128 is a generic OBD-II trouble code that means: Coolant Thermostat – Coolant Temperature Below Regulating Temperature. The engine control module (ECM) stores this code when it detects a fault related to: Coolant Thermostat.
What causes code P0128?
The most common causes are: Thermostat stuck open or closed; Low coolant level or a cooling system fault; Faulty sensor or component.
How do I fix code P0128?
Start with these steps: Read all stored codes and freeze-frame data with an OBD-II scanner; Check the coolant level and look for leaks; Replace the thermostat and bleed the cooling system; Clear the code and road-test the car to confirm the repair.
Is it safe to drive with code P0128?
Severity: Low. Usually yes in the short term. The car normally runs fine, but fix it soon to avoid failing an emissions test or causing further problems.