Can A Bad Coolant Temperature Sensor Cause Car Not To Start

Many different reasons can cause vehicle failure. There will undoubtedly be reasons you may be familiar with engine failure, incomplete axles, or poor carburetor performance. 

Besides, there are many reasons that we can expect less, such as the problem of the sensors in general and the coolant temperature sensor in particular. 

So why can a fault in such a small part have such a big effect on the car, and how do we handle it? Please refer to the necessary information in today’s article.

What Is a Coolant Temperature Sensor? 

What Is a Coolant Temperature Sensor

First, we need to know some basic information about the coolant temperature sensor before diving into why this part can cause your car to stop working like a bad ignition switch.

First, the coolant temperature sensor and many other sensors that appear scattered throughout our vehicles are modern electronic devices that have the role of recognizing the minor changes in the area it takes on. 

The manufacturer usually arranges it inside or near the car engine with this device. Besides, the leading role will be to manage and notify the temperature, precisely the machine’s coolant temperature.

Thanks to this appearance, the engine material’s temperature and the vehicle are becoming more and more perfect. 

How Does a Coolant Temperature Sensor Work?

The working process of the coolant temperature sensor in detail is quite complicated when you have to know electronics to understand, not just read and perform simple steps like when you clean o2 sensor. However, in contrast to analysis, the summarization of activities is much simpler.

We can understand that the coolant temperature sensor will control the coolant temperature in your car’s engine. 

This unit then records and sends this information to the Engine Control Unit (EUC). This information will be calculated to give the correct parameters to notify the system and users promptly.

Can A Bad Coolant Temperature Sensor Cause a Car Not To Start?

Can A Bad Coolant Temperature Sensor Cause a Car Not To Start

The lousy coolant temperature sensor does not directly affect the car’s ability to work or not. However, that does not mean that we deny the influence of this part indirectly on the vehicle’s ability to start. 

Because the failure of this part can cause the engine temperature to rise suddenly, causing phenomena such as the car temperature gauge goes up and down while driving. It will destroy parts sensitive to heat in more severe cases.

How To Tell If Your Coolant Temperature Sensor Is Not Working Correctly?

The most obvious sign of a bad coolant temperature sensor is that this device cannot reasonably control the temperature of the coolant, thereby causing overheating of the vehicle. 

In other words, a sudden increase in vehicle temperature is one of the most explicit warnings that the temperature of the coolant is not stable.

Usually, with temperature-related problems, you can see the symptoms right below quite often.

  • The engine temperature gauge shows an uneven temperature (should read somewhere between 88 and 90 degrees Celsius when the car is warm)
  • The engine is too hot
  • The check engine light is on your dashboard.

In addition, there are some symptoms below that you can look for further if you notice the presence of these problems on your vehicle.

Problems with startup

If the engine starts and immediately stalls and quickly disappears after starting, it is most likely caused by a bad coolant temperature sensor. 

Because the coolant temperature sensor can provide wrong results to the ECU, causing this part to stop the vehicle and check it later for operation.

Wrong temperature sensor

Here everything is quite the opposite. The coolant temperature sensor may give the ECU false indications that the engine is cold. Therefore, the engine will only need to fill up with fuel. Furthermore, the code P0172 may appear in this situation.

Increase fuel consumption

It is a consequence of the above symptoms. If the engine is flooded with fuel, then consumption will increase.

How to Test the Coolant Temperature Sensor?

There are quite a few different ways to check that the coolant temperature sensor works properly. However, there are some ways to do it that are simpler than others, especially the two ways below.

First one:

  • The crazy way is also the easiest and fastest way to check the coolant temperature sensor; you will not need too many tools but simply opening and closing aids such as screwdrivers.
  • We will then need to find the sensor location and remove this part from the slot. At this time, the engine will enter emergency mode, the cooling fan will turn on, and the fuel mixture will be based on the readings of other sensors.
  • If the motor begins to work better simultaneously, then the sensor needs to be replaced.

Second one:

  • The following way will require you to use a very familiar tool in interfering with the vehicle’s electronic systems to perform operations such as disabling check engine light permanently. That device is no stranger to the OBD itself.
  • To operate, you first need to check the temperature indicators on a cold engine, for example, in the morning.
  • The readings should correspond to the ambient temperature plus some minor differences, but not too big of a difference.

Frequently Asked Questions(FAQ’s)

1.Can the temperature sensor affect the engine starting?

If the sensor reads that the temperature is too high, the computer will immediately perform the test and stop your car, making moving more difficult.

2.Can a stuck thermostat cause coolant loss?

The thermostat does not allow the coolant to flow when stuck in a closed position.

3.How do I know if my coolant is circulating?

Start your car’s engine and allow it to idle. Look over the radiator neck to see if the coolant is flowing.


After today’s article, we hope you got the most suitable answer to the question: can a bad coolant temperature sensor cause a car not to start. Thereby, it makes maintaining and using the vehicle more efficient and safer.

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