The fault code P0128 generally indicates the same fault for all makes and models of vehicles. However, if you are getting a P0128 fault code as it may indicate a different problem in some brands and models, you should definitely check the technical service booklet of your vehicle. In this article, we will look for an answer to the question of what P0128, which is an OBD-2 fault code, means.
Whether gasoline or diesel, an explosion constantly occurs inside internal combustion engines. As a result of this combustion, a temperature of up to 400 degrees is produced. If the engine didn’t have a cooling system, your car’s engine could run for a maximum of 10 minutes. After that, the overheated engine would die. However, manufacturers have built an engine cooling system to prevent this situation. An engine should not run too cold, as well as not be too hot. Because an engine has a normal operating temperature. This corresponds to a temperature of around 90 degrees today. There is a part called a thermostat for the engine to adjust the operating temperature. The thermostat, located between the radiator and the engine block, works as follows. After the engine starts first, the thermostat is turned off until the engine comes to the desired temperature. When the water temperature reaches 90 degrees, the thermostat spring is pulled back and allows the water to go to the radiator to be cooled.
P0128 Fault Code Meaning: The thermostat is a simple mechanism. Inside there is a candle-like substance that melts at 90 degrees. As the engine heats up, this substance passes into a liquid state, allowing the thermostat valve to be pulled back. However, if the engine control unit (ECU) detects a malfunction in the operation of the thermostat, it will give the error code P0128 Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature).
P0128 Fault Code Symptoms
- Failure to heat the heating of the car
- Sound operation of the engine
- Increased fuel consumption
- Burning of the engine malfunction lamp
- The temperature indicator drops too low when driving
- Engine overheating due to the thermostat remaining in the off position
P0128 Fault Code Causes
- Lack of engine coolant (antifreeze)
- Thermostat water leaks
- Radiator fan failure
- Coolant temperature sensor (ECT) malfunction
- Faulty intake air temperature sensor (IAT)
- Burning of the top cover gasket
- Radiator blockages
P0128 Fault Code Repair, Fixes and Solutions
If the engine malfunction light in your vehicle gives the fault code P0128 when you connect it to the computer after it is lit, check the radiator water level you need to do first. Then look for a leak in the connection hoses located between the radiator and the engine. If that’s fine, check to see if the computer gives you other OBD-2 codes. If there is, you should first turn to the solution of those codes. If you only have error code P0128, you will need to change the thermostat of your car. Finally, you need to connect to the computer again and delete the code.
Source: P0128 Fault Code – Thermostat Fault Error Code