P1289 Error Code: Cylinder Head temperature Sensor Malfunction

Diagnostic error codes appear when there is a malfunction in specific areas of your car. However, interpreting this code usually requires the help of an expert or consulting various sources. The P1289 error code arises when there is a malfunction with your car’s cylinder head temperature sensor.

Going further in this article, you will learn more about the cylinder head temperature sensor and its primary function, we will then move into discussing the causes of this error code, the symptoms you may observe, and then how you can troubleshoot this code. 

The cylinder head temperature sensor 

The electronic control module (ECM), considers temperature as an important factor before sending instructions to other parts of your car system. The air intake or coolant system is there when the engine gets too hot, and more fuel will be needed to warm up a cold engine. The cylinder head temperature sensor is one of the components that notifies the ECM about the temperature of a specific area in your car, and this area is the cylinder head.

The cylinder head temperature sensor is usually located between the 2nd and 3rd cylinders on top of your engine and it is commonly found in air-cooled engines.

Causes of the P1289 error code

The P1289 error code is triggered when there is a malfunction with the cylinder head sensor and here are some of the common causes of these malfunctions.

Faulty connections to the sensor

There are electrical connections that run from the cylinder head temperature sensor to the ECM to give input to this system and generate output. When these electrical connections have some kind of fault, the sensor doesn’t function like it usually does. 

The sensor terminals are corroded 

The sensor terminals serve as the starting point for the electrical connections that run to the ECM. When these terminals are corroded, they don’t function as effectively as they used to, and in some cases, they may not function at all.

Low coolant levels


A coolant moves through your car system when it’s at work and it absorbs heat and transfers it to the radiator. When the coolant level in your car drops, your car will overheat without the proper channeling of heat outside the car system.

Overheating can lead to several car parts becoming damaged, and this includes the cylinder head temperature sensor. 

Symptoms of a P1289 error code

When this error code is triggered in your vehicle, several signs indicate so. Here are some of the common symptoms of a cylinder head temperature sensor malfunction:


One of the common signs of this malfunction is overheating of your car components. This is because your low coolant levels have caused overheating which is not obvious and has damaged your sensor. When the heat generated from your car is more than usual, it may be a sign of this code. 

The check engine light comes on

The check engine light is a yellow or orange light that usually appears on your car’s dashboard display screen when there are faults with your car’s internal system. This warning light is usually displayed in the form of an oil jug.

Poor fuel mileage

As we have discussed earlier, a malfunction in this sensor can lead to an incorrect fuel-to-air ratio which means more fuel will be used for combustion than usual. You may notice that your fuel level goes down faster or you may find yourself buying gasoline more regularly than usual, this is an indication of a coolant problem. This is especially the case when it is coupled with black exhaust smoke.

Difficulty starting your car

When the fuel-to-air ratio in your car is incorrect, you might have an overload of fuel in your car system that may make your car difficult to start. This is usually the case with a malfunction with the cylinder head temperature sensor or other coolant malfunctions. 

Rough idles

When you have issues with your cylinder head temperature sensor, your car may experience rough idling. Rough idle is observed by the uneven movement of your car while driving. Instead of having a smooth drive, your car will be shaking or bouncing.

Black exhaust smoke


The cylinder head temperature sensor provides valuable input to the ECM that helps determine the fuel-to-air ratio for combustion. When this sensor is faulty, it sends incorrect signals to the ECM which causes it to burn excess fuel for combustion.

This abnormal combustion ratio generates black smoke from the exhaust pipe which is harmful to the environment and signifies a problem with this sensor or other components of the cooling system.

Troubleshooting P1289 error code

To troubleshoot a P1289 error code, you need to diagnose it first, then determine the possible cause of the problem, and then execute a solution. You can diagnose this code by contacting an expert to help you out or by doing it yourself using an OBD-II scanner.

If you prefer to consult an auto-expert for diagnosis, you can also get them to help you fix the cause of this error code. However, here are some possible ways you can get rid of this code:

Up your car’s coolant fluid

We have already established that a low coolant level in your car can lead to overheating which can damage car components, including the cylinder head temperature sensor. Check your coolant reservoir to check its level. The coolant can be water or it’s usually a fluid with a vibrant color like green, orange, or yellow.

If there your coolant level is low, top it up with the appropriate fluid.

You also want to check if your coolant is leaking which can cause a drop in the level of the fluid. If this is the case, fix the leak immediately.

Check the cylinder head temperature sensor electrical connections

The electrical connections from this sensor to your car’s ECM may be faulty which is why you got this code. You can contact an expert to help out with this or consult appropriate directions or instructions to make the changes necessary. 

Check sensor terminals

The terminal of your cylinder head temperature sensor is the foundation of signal communication between this component and the ECM. Check the terminal to see if they are corroded. If the terminals are corroded, you may need to replace them or entirely replace the sensor. 

Tips for preventing this code

  • To prevent your car from triggering this code in the future, here are some helpful tips to help you out
  • Use quality or recommended coolant for your car.
  • Don’t strain your engine with unnecessary aggressive driving.
  • Regularly check for coolant leaks. One way to do this is to check beneath your car for the presence of fluids, especially fluids with the same color and smell as your coolant.
  • Clean your engine bay occasionally to prevent any debris block that can lead to overheating.
  • Beware of using excess sealant when replacing your gaskets or other nearby components. This can affect the reading sent from the cylinder head temperature sensor.


One of the common diagnostic codes you may receive from your car includes the P1289 error code and it indicates a malfunction with your car’s cylinder head temperature sensor. After reading this article, you should have learned more about this component, its primary functions, and the possible reasons it might malfunction to generate this code.

You should also have an idea of the symptoms associated with this code, how to diagnose it, and the possible fixes that can be carried out. Lastly, we have dropped some prevention tips to ensure that your car does not trigger this code.