A turned-on check engine light is often a cause of headaches for many drivers. But before you start to worry, check other symptoms that followed the warning light. If you notice a problem with engine temperature, the issue could be in an engine cooling system. To be sure, use an OBD-II sensor, to be sure. If after the scan you get a P0128 error code, the problem is usually in the engine coolant thermostat.
What can be a cause for a P0128 code? In most cases, the problem is in a faulty thermostat that is regulating the temperature of the cooling fluid. The other frequent cause is problematic wiring of the thermostat. In some rare cases, the cause for the P0128 code is a faulty radiator fan.
In every case, you don’t need to worry; the problem is not critical. You won’t feel any performance or drivability issues. But you should think about fixing the issue because, in the long run, it can cause problems for the engine.
Understanding the Basics of OBD-II Codes and P0128 OBD2 Code
Modern cars employ several sensors and computers. Their main purpose is to monitor the work of the vehicle and notify the system if there is a problem. The OBD-II code system is developed for that purpose. The OBD-II codes are unified error codes that ease the diagnostics of different errors.
OBD-II Codes Explained: The Nitty-Gritty of Your Car’s Health
The OBD-II codes are generic trouble codes that point out the part that is in trouble. Everyone that has an OBD-II code scanner can conduct scanning and code reading. Once you identify the code, you should determine what does it mean. Depending on the error, there can be several problems that require identification. There comes a skillful mechanic or any type of tutorial that you can use for help.
The P0128 Code: More Than Just a Number
The P0128 code is connected to the cooling system. After the driver starts the engine, the coolant should reach a temperature of 160° F in 15 minutes. Once it does, the coolant temperature sensor is there to keep the temperature above 160° F.
If the coolant temperature doesn’t reach that temperature, or it takes it too long, the P0128 trouble code is signaled by the engine control module.
Decoding the P0128 Code: What It Means for Your Car
The main problem behind the P0128 is the low temperature of the coolant. When this happens, the engine will not work at a proper operating temperature.
The Science Behind P0128 Code: Coolant Thermostat Malfunction
The proper temperature of the engine is between 195° F and 220° F. The thermostat needs to be in a closed loop so the engine can reach that temperature. If the thermostat is in an open loop for too long, the engine cannot gain a much-needed temperature level.
Common Symptoms When the P0128 Code Appears
The first thing most drivers notice before they diagnose the P0128 OBD-II code error is a turned-on check engine light. But, even before that, the driver can see that the engine temperature on the gauge is lower than usual. Sometimes the temperature can all of a sudden rise and fall.
If the driver is not checking the temperature of the engine, or the car doesn’t have a gauge, other code P0128 symptoms are high idle and poor fuel economy.
What Causes a P0128 Code? Pinpointing the Culprit
The two most common culprits behind a P0128 are a faulty thermostat or the coolant temperature sensor and its wiring. In some rare situations, there are noted cases where low engine coolant levels caused this error.
TL:DR: It is worth checking the radiator fan.
The radiator fan cools down the engine and the coolant. If it is stuck in one position, that will cause the coolant to heat slowly.
The Impact of the P0128 Code on Your Vehicle’s Performance
The main reason many drivers don’t address this error code immediately is the lack of any significant performance issues.
P0128 Code and Fuel Efficiency: What You Need to Know
When the engine is running at a lower temperature than it should, it starts overcompensating with using extra fuel. That leads to increased poor fuel mileage. That is considered to be the biggest issue revolving around this error.
Safety Concerns Linked to P0128 Code
This error is considered to be low to middle-level severity. You can drive the car after you diagnose the error but do not forget about the cause of the problem. The only thing that you should check out is the level and the state of the coolant. If the coolant reservoir is leaking, there will be a lack of coolant in the system. Also, if the issue is worn and dirty coolant, replace it.
But, even though this error message is not too dangerous, and you can drive some time with it, it is best to fix it as soon as possible.
P0128 Code and its Impact on Vehicle Longevity
If the car with a P0128 code is driven for a short term, it will not cause any major problems with the car. The only problem you will notice is excess fuel consumption and somewhat increased engine work on idle. But, the irregular temperature of the cooling fluid can cause problems if left unchecked for a long time. That will cause engine damage as a result of expensive damage to fix.
Proven Methods to Troubleshoot and How To Fix Code P0128
Troubleshooting a P0128 is focused on checking the cooling system of the car.
DIY Fixes for P0128 Code: A Step-by-step Guide
- Use an OBD-II scanner to check for errors. If there are any other codes other than P0128, resolve them first
- Visually inspect the coolant reservoir and coolant level. Sometimes a low level of fluid or a coolant leak can cause a P0128 error code. Check if the coolant is on optimal levels, and when was it changed last time
- Check the coolant temperature sensor. For this, you will need to switch the multimeter to resistance testing. The resistance value should change with the temperature. If the readings are the same, then you should inspect the wiring of the sensor or the sensor itself
- Inspect the thermostat. The P0128 diagnostic trouble code is often a result of a stuck engine coolant thermostat. Check the coolant hose and the temperature of the coolant flowing through it. Be careful when doing this to avoid burning. If the radiator hose takes more than 5 minutes to heat up, the thermostat is constantly open.
Check Out How to Fix P0128 Engine Code in 3 Minutes:
Essential Tools to Solve the P0128 Code Mystery
To diagnose the issue, you will need a multimeter and an OBD-II code reader.
When to Seek Professional Help for P0128 Code
If none of the solutions mentioned above resolve the issue, you should contact a professional.
FAQs about the P0128 OBD2 Code
Is Driving My 2005 Chevrolet Trailblazer with a P0128 Error Code Dangerous?
No, driving a 2005 Chevrolet Trailblazer with a P0128 error code is not dangerous. The engine will be running a little less hot, but it cannot result in imminent danger.
Why Do I Get a P0128 Engine Running Cold Despite Changing the Thermostat?
The most common reasons for getting the P0128 error code after changing the thermostat are:
– Some cars have more than one thermostat. You may change the wrong one
– Low level of cooling fluid. Before you change the thermostat, you should check the level of the cooling fluid
Is the P0128 Error Code Serious?
No, the P0128 error is not serious. If you have a predefined road trip, you can take it, but try to resolve the problem as soon as possible. Driving for a long time with an engine that is working at a low temperature is not good for the engine as a whole.
How Long Can You Drive If You Have a P0128 Code?
There is no certain answer on how long you can drive with a P0128 code. It all depends on the car and the problem. The engine will have certain problems when working in lower temperatures, and you will notice bad fuel mileage, so repair it as soon as possible.
Will the P0128 Error Code Clear Itself?
No, the P0128 error code won’t clear itself. The engine coolant temperature sensor will not be able to raise the temperature enough. That will keep triggering the powertrain control module to issue the P0128 error.
Ensuring a P0128 Code-Free Future: Preventive Measures and Tips
Regular Maintenance to Prevent the P0128 Code
Since the P0128 code is usually connected to the cooling system, regular inspection and maintenance is the only thing you can do.
Regularly check the coolant tank, and pay attention when you need to replace the coolant. Keep an eye on the coolant level, and don’t let it get old and worn.
Investing in Reliable OBD-II Scanners to Catch P0128 Code Early
OBD-II scanners are now easy to get. There are a lot of manufacturers that offer them, so you can take your pick. First, you need to know what you want from the scanner. After that, you can look at the scanners that will satisfy your needs. Always add a couple more dollars when buying a scanner. In the end, it will pay itself off with good diagnostic capabilities.
Need More Help with a P0128 Code?
As we said, diagnosing and repairing the P0128 code is not difficult. There are a couple of things to check out, and after that, you are good to go. Drivers often disregard this error code because it is not that serious and they don’t impact the car’s performance.
But do not forget to resolve this issue. Driving a car with a cold engine is not good in the long run. Lower the cost of labor required to fix this issue and visit a mechanic.
