Service Engine Soon Light Is On – What’s Wrong?

Service Engine Soon Light Is On – What’s Wrong?

In today's day and age, cars are becoming more and more complex. As such, there are quite a few possible reasons why your service engine soon light is on. It is essential for you to properly diagnose the cause of these particular issues which means that you ought to take your car in for an inspection. Possible causes of a service engine light:

• Routine maintenance alert
• Low engine fluid levels
• Faulty or loose gas cap
• Spark plugs and wires in need of replacing
• Faulty oxygen and mass airflow sensors
• A faulty catalytic converter
• Faulty ignition coil
• Electrical issues
• Faulty EGR valve
• Leaking engine vacuum hoses

Routine Maintenance Alert

More often than not, why your service engine soon light comes on is literally because your engine needs servicing. Engines are not built to last forever, this means that every once in a while, some things should be replaced or serviced.

Whenever you encounter the service engine soon light, be sure to take your car in for a proper diagnosis. If it's just routine maintenance, you ought not to worry. Sometimes it's just a small niggle that needs fixing, however, sometimes it can be way more complex than that.

Low Engine Fluid Levels

For your engine to function properly, it needs lots of lubrication. It’s the same story with your transmission, brakes, and your cooling system. From time to time, these fluids should be changed or topped up, and if they are not, they can occasionally prompt up the service engine soon light.

Whenever this happens, you ought to check your car for possible leaks. An easy way to know is to just top up the fluids and leave the car parked for a while. If the car is indeed leaking, the ground under the car should have stains on it.

Faulty Or Loose Gas Cap

Your fuel tank has to be sealed at all times. This is necessary from a safety standpoint and to stop your fuel from coming in contact with the elements, and thus contaminating the fuel mixture. Whenever your fuel cap is not sealed accordingly, it usually prompts up the service engine soon light.

Ordinarily, all you have to do is to make sure your fuel cap is sealed as intended. If you are unable to completely seal off your fuel tank, this means that your fuel cap is malfunctioning and you ought to take your car in for a diagnosis.

Spark Plugs And Wires In Need Of Replacing

Spark plugs are designed to ignite the fuel and air mixture inside the combustion chamber in an effort of creating mechanical energy that propels your car. Even though they are designed to last for a long time, they are not designed to last forever.

Sometimes they can last upwards of 100k miles. However, they are known to sometimes malfunction prematurely, and they can also cause your service engine soon light to come on. Faulty spark plugs and wires are also known to negatively impact the combustion process. So if you experience engine misfiring or jolting, a faulty spark plug is likely to be causing it.

Faulty Oxygen And Mass Airflow Sensors

A car engine oxygen sensor is a device tasked with regulating the levels of oxygen inside the combustion chamber. For your car to perform at its best, engine oxygen levels should be at an exact level. A mass airflow sensor works in conjunction with the oxygen sensor to ensure that the levels of fuel are also at an optimal level.

Occasionally, these two are also known to cause your service engine soon light comes on. Your ECU is tasked with receiving information from the oxygen and mass airflow sensors, and if the ECU realizes severe fuel or oxygen discrepancies, it usually results in a service engine soon light.

A Faulty Catalytic Converter

Faulty oxygen and mass airflow sensors can sometimes even cause your catalytic converter to malfunction. This is by far the most serious issue commonly associated with a service engine light because the catalytic converter is crucial for your car to pass emissions regulations and to cleanse the atmosphere from all the harmful exhaust pollutants.

Be that as it may, it is fairly uncommon for a catalytic converter to malfunction prematurely if your oxygen and mass airflow sensors are functioning as intended. However, if they are not, they can cause such issues. Nevertheless, be sure to take your car in for a diagnosis, the worst-case scenario will likely require you to invest in a brand new catalytic converter.

Faulty Ignition Coil

If your engine coils are malfunctioning, you are likely to experience loss of power, a stalling engine, and way worse fuel economy. This can be disastrous for your engine if you don’t recognize this issue in time. As such, be sure to take your car to a professional whenever you are not able to pinpoint any issue specifically.

A common symptom of a faulty ignition coil is car stalling and jerking randomly while driving. This can be extremely dangerous, especially if you are driving on a highway. To proactively solve this issue, be sure to check the coil's insulation every 25k miles or so.

Electrical Issues

If your battery voltage is low, it should also prompt the engine light on your dashboard. This issue is easily fixable by simply replacing the battery. However, sometimes the alternator might cause your battery to go low, so be sure to visit a technician before you opt for buying a new battery.

Many possible issues could arise from the electrical system, some of them might be directly connected to the engine while others could only be auxiliary systems. Either way, some of them are known to prompt up the check engine light, so be sure to pinpoint the issue before you drive the car.

Faulty EGR Valve

The EGR or exhaust gas recirculation valve is an intricate piece of machinery designed to battle your car’s harmful emissions by redirecting the exhaust gasses back to the cylinders while also increasing efficiency. However, if you experience rough idling or misfires, it often means that your EGR valve is to blame, especially if the check engine light is on.

It’s best to take your car in for a diagnosis as issues such as these can cause more issues down the line. Even so, you will momentarily feel a distinct lack of power, worsen fuel economy, and difficulties passing emissions testing.

Leaking Engine Vacuum Hoses

If your engine's hoses are leaking, it might not even prompt the engine light on if the leak is not severe enough. However, if your engine tends to idle at higher RPM than usual, it means that your engine hoses are probably leaking.

If the issue persists, it will also prompt the service engine light because issues such as these can ultimately lead to your engine completely shut off. Another common symptom of a hose leak is the engine hissing whenever you rev it up.

FAQ Section

Is A Service Engine Light Bad?

It depends on the culprit. There are many reasons why the engine light comes on which do not affect your everyday driving. This means that there are lots of instances when you can drive your engine without worrying about it. However, it's always best to diagnose the issue as soon as possible.

How Much Does A New Gas Cap Cost?

If your check engine light is on, the first thing you need to check is the fuel cap. If your fuel cap is not tightly in place, and you can't get it to click, you need a new gas cap. It’s best to replace the gas cap right away because a new one costs around $10-$30, but if you don’t replace it, you are likely to pay much more for increased fuel costs.

How Much Does A New Oxygen Sensor Cost?

The general rule of thumb is that you should never ignore a service engine light, no matter how benevolent the issue might seem. As such, many motorists report that a faulty oxygen sensor is the most prevalent reason why the engine light comes on. This means you will have to replace it, and a new O2 sensor costs around $400 on average.

However, if you don’t replace it, you are likely going to experience up to 50% less fuel economy over time, and that’s if nothing else goes wrong with the sensor itself.

How Much Does A New Catalytic Converter Cost?

A catalytic converter is a vital component when it comes to the car’s emissions system which means that replacing one is a rather hefty expense. On average, a new catalytic converter costs around $1200, but these prices vary depending on the car’s make and model year.

How Much Does It Cost To Replace The Spark Plugs And Ignition Coil?

If your spark plugs are to blame for the service engine light, it's best to replace them right away because they only cost between $15-$100 depending on how many of them need replacing. If you don’t do it right away, you are risking your ignition going bad, and if it does, the repair costs could easily climb over $400.