Updated at: 27-07-2023 - By: Lucas

Technology has become an important part of modern cars. Most cars have computers on board that keep track of how well each engine part is working. If there is a problem, the computer records it as an error code.

The service engine soon light is one of the problems that a computer like this can find. This article talks about what it is, why it happens, and how to fix it.

When this light comes on, it could be telling you that your car’s sensors have found a problem.

Most of the time, it could mean that your car’s engine has a small problem. It could also mean that something is wrong with the electronics in your car.

For some other brands, it could mean that you need to do some regular maintenance. These kinds of services could be like oil changes. It could also mean that your spark plug needs to be changed.

If you have a Nissan, the service engine soon light might mean that the gas cap is loose. It can also be a sign of a big problem, like the possibility that the engine will break down.

Want to know how long gasoline stays good for? – Read on.

Why You Shouldn’t Ignore this Light

Even if this is just a warning, it’s a good idea not to ignore it. Most of the time, the service engine soon light lets you know about a small problem before it gets worse.

When you see this light, you might not have to pull off the road and take your car to the garage. But it’s important to make an appointment to get it fixed.

You shouldn’t pay attention to this warning because it could lead to a bigger problem if it isn’t fixed. If it gets worse, it could cause serious damage to parts of the car. If you wait to fix this, it might end up costing you a lot more.

Common Reasons for the Service Engine Soon Light

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1. A Loose or Faulty Gas Cap

Yes, this is one of the things that can make the “Service Engine Soon” light come on.

The good news is that it’s easy and cheap to fix. It’s a problem that you can even fix on your own.

2. Faulty Oxygen Sensor

It is very important that your car has the right amount of oxygen to gasoline. It is necessary for your car to run at its best.

The engine will break down if there isn’t enough oxygen. It makes it run “rich” on the gasoline that is left over after the fuel is burned.

On the other hand, your engine can also be hurt by too much oxygen. Most of the time, it will make the engine run badly. In the worst cases, it could even hurt the engine.

Because of this, your engine sensor is very important. With the help of the engine computer, the sensor figures out and changes the amount of air to fuel. If a sensor is broken, the computer can’t change the amount of air to gasoline.

Because of this mistake by the computer, the lights turn on. If you don’t check on a broken sensor right away, it could cause the engine to lose power. In the end, it could hurt your spark plugs and your catalytic converter.

3. Spark Plugs & Wires

Spark plugs and wires often stop working after a while. So, they wear out and need to be replaced after a while.

If your plugs and wires are broken, they could change how the fuel burns.

Plugs that aren’t working right are easy to spot. You will feel a little jolt as you speed up.

4. Mass Airflow Sensor is Faulty

In a car, the mass airflow sensor is very important. The main thing it does is measure how much air is going through the air filter.

After figuring out how much fuel the engine needs, it tells the computer. The amount of fuel is based on how much air goes into the engine.

If the mass airflow sensor is broken, you won’t get as good of gas mileage.

Your car might also start to lose power.

The mass airflow sensor can also be very dangerous if it isn’t replaced when it needs to be. The spark plugs and oxygen sensor can get broken. The catalytic converter can also be hurt by this.

How to Fix the Issues and What to Do

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1. A Loose or Faulty Gas Cap

First, take off the gas cap and put it back on. Take the car for a short drive. The light should be able to be turned off by the Onboard Diagnostic (OBD) system.

But if the lights are still on after a few trips, you may need to replace the gas cap.

You will need to get a cap that fits your car’s exact brand.

Once that’s done, drive the car a few more times. This drive is for resetting the ODB system.

If the lights are still on after doing all of these things, you may need to take the car to a garage. Then you can get an accurate diagnosis of what the real problem might be.

2. Spark Plugs & Wires

You don’t have to wait until the spark plugs and wires are completely worn out before replacing them. Check the schedule that the car’s maker gives you and replace them on time.

You can do this on your own at home. You only need a few simple tools, including:


Ratchet and sockets

Set wrench

Spark-plug wire pliers, if needed

if needed, goggles

Your car needs a new set of spark plug wires.

Needle-nose pliers, if needed

Floor jack, jack stands or wooden blocks

How To Change The Spark Plug Wires

Start at one end of the engine and work your way toward the other. To avoid connecting a wire to the wrong cylinder, only replace one spark plug wire at a time.

Wait until the engine has cooled down so you don’t get burned.

To make it easier to get to the plug wire, you can move anything that’s in the way. Some of these parts are the engine cover, air cleaner duct, and radiator fan shroud. To do this, you will only need a screwdriver.

Choose one spark plug wire from one end of the engine. As you pull on the wire boot, hold it in your hand and twist it from side to side. If you can’t reach the boot with your hands, a spark-plug wire plier might help.

If the wire is held in place by clips, take them off.

Check the other end of the wire and unhook it from the distributor or ignition coil. If a spring clip is holding the boot to the distributor, you may need a pair of needle-nose pliers.

Faulty Mass Airflow Sensor

After opening the hood of your car, look for the MAF sensor on the air cleaner assembly. It is between the housing for the air filter and the throttle body. But in some other models, the MAF sensor is in the housing for the filter.

Check to see if there is a plug on the air duck. After the air filter housing, you’ll find the air duct. If you can’t find it, you can look in your repair manual.

Connect the sensor to the electrical plug. Check to see if you can probe the wires from the back. If that’s not possible, use a pin to poke holes in the wires as you do your tests.

Note that you may need to wrap the wires with electrical tape if you have poked a hole in them. The wrapping keeps them from rusting down the road.

Look for the power, ground(s), and signal wires on the electrical connector. You can look in your repair manual or online to find this information.


In conclusion, you should fix any problem that makes the Service Engine Soon light come on.

The catalytic converter could break down if these things happen. It can be very expensive to fix a catalytic converter.

Consequently, ensure you maintain your vehicle. Do not ignore any small problem, but ensure you fix it on time. By doing this, you will avoid or minimize major repairs on your vehicle.