What Is P0118 In Honda Civic? Code Explained with Insights

There can be various codes appearing on the dashboard of our Honda Civic. Although some of them are not that serious, others could be alarming. So, a common code of these that you might see on the Honda Civic is P0118.

Now, you may wonder, what does the code P0118 mean in Honda Civic?

The code means the engine coolant of your car is getting very cold. This indicates that the coolant might be passing a temperature range of -4 degrees Fahrenheit at the moment, which needs help.

This answers your question in brief. However, you need to get into the details that we got here in order to fix this issue.

So, read along till the last of our article.

What Does the Code P0118 Indicate?

You may be running your car normally even after seeing the code P0118 on your car’s computer. However, you actually are not concerned that there is something going on inside the engine of your car.

So, that brings the question, what does the code P0118 mean? Well, this means the ECM of your car reads an unusual temperature of the engine coolant. 

To be precise, this means the coolant has reached a temperature of -4 degrees Fahrenheit or even lesser. We know the engine coolant prevents the engine from being overheated.

However, that does not mean it would be as cold as possible! Now, if you think it could be a good thing for now, you are wrong.

If the engine coolant keeps on getting cooler, it will start freezing up. Due to this, the engine linings of your car might start getting clogged. As a result, the engine would start stalling as they are worked up and overheated.

Note that there would also be a significant lack of lubrication when this happens. So, if you see this code on the dashboard of your car, get to it and fix this as soon as possible.

What Are the Symptoms of Getting P0118?

Knowing the symptoms of a problem is quite an important thing. This is because addressing the early stage of a problem can prevent adverse consequences to a good extent. So, here we have got the symptoms of getting P0118.

• A significant drop in the economy of your car’s fuel.
• You may be struggling to start the engine of your car at times, especially if it was turned off for a while.
• There might be black smoke coming out of the exhaust pipe of your car.
• You may be experiencing sudden stalling and shaking of your car in the middle of the journey.
• Sometimes, you may hear some low noises too that are coming from the inside of the car engine.

So, these are the symptoms of engine coolant getting way too cold.

What Causes the Code P0118?

In this segment, we will get to know about the main reasons behind the issue with the engine coolant. 

Note that the reasons behind this would vary from time to time and situation to situation. So, here we have got all the possible causes of it. Take a look here.

Reason 1: Bad Engine Coolant Temperature Sensor

The engine coolant temperature sensor reads the temperature and sends signals to the engine’s control unit. With the help of this, the fuel quantity and ignition point are correctly maintained.

Now, if the engine coolant temp sensor turns bad, the coolant would start having issues, eventually dropping the temperature.

Reason 2: Broken Electronic Controlled Transmission Connector

A broken electronic controlled transmission connector can lead to a number of problems. Now, talking about engine coolant, this can also be responsible for abnormal temperature.

That means the engine coolant can get too hot or cold due to a bad connection of the electronically controlled transmission to the sensor.

Reason 3: Engine Coolant of Low Quality

If you are not using engine coolant of good quality, you will definitely face issues with its temperature. Not only that but if you have kept the same coolant for a really long time, there would be this problem too.

Thus, you have to make sure that you keep on changing the coolant over time. On average, you need to refill it after every 30,000 miles of a run.

So, these are the main reasons behind the problem with engine coolant. Remember that there can be some other reasons related to internal functions too.

How to Resolve the Code P0118?

Resolving the code P0118 can be tricky. Not everyone knows the right process, which can deteriorate and lead to many other additional issues. So, here we have got the 2 most effective methods you can try. Take a look.

Method 1: Replace the ECT Sensor

First, you need to inspect the ECT (Engine Coolant Temperature) sensor of your car. To do it, remove the sensor and take a multimeter to see the readings. Now, you must be getting readings ranging from 2000 to 3000.

Now, if you do not get readings in this range, wait for a while. Keep the sensor in an airtight bag for about 30 minutes and take readings again.

This sometimes fixes the problem, but if you still have not got it right, the sensor is faulty. So, the ECT sensor needs replacement.

However, if the ECT is alright but the engine coolant still got issues, move on to the next method.

Method 2: Replace the Thermostat

Remove the thermostat that is placed near the water pump on the cylinder head. Make sure you put your car turned off for at least 30 minutes so that the engine is cool enough.

Now, install a new thermostat to get started. While installing the thermostat, you have to put the short end towards the hose. On the other hand, the long end would face the engine.

You would see the jiggle valve of the thermostat, which would be pointed straight up to the top of the engine so that the air can get through to it. 

Now, once you install the new one, do not start the car instantly. Hopefully, this will resolve the problem!

So, this is how you can resolve the problem of engine coolant.

How Serious Can the Code P0118 Be?

The code P0118 is not considered to be extremely dangerous for your car. However, you have to remember that this would get you through a number of mild adverse consequences. So, how serious is the code P0118?

Well, if you have this, your car would go to a mode referred to as failsafe mode. Due to this, the engine would start running more than it usually does and would become rough over time.

As the temperature of the coolant is way colder, the engine would try to reach the normal temperature by working up more.

Due to this, the consumption of fuel in your car would go up, including the carbon fouling of the engine.

Now, if you are fixing the issue after a certain period of time, your engine may start stalling too. Although this may hardly have any long-term or permanent effect on the car engine, you still have to be careful.

Therefore, P0118 on the Honda Civic is actually not that serious if you can look at it on time.

Frequently Asked Questions

The Final Words

Now you know all about the code, P0118 Honda Civic, in detail. We believe you would have no more complications in resolving the issue on time.

However, do not hurry with any step while fixing the issue, especially if you have less knowledge in the field. Make sure you seek professional help whenever you need it.