What Causes Reduced Engine Power and How to Fix It?

Is your vehicle displaying the engine power is reduced warning light? Don’t panic; learn what causes reduced engine power light to come on and how to fix it quickly.

Is, off late, your vehicle’s instrument cluster display showing the message – Engine Power is Reduced? Is the check engine light also on? Are you thinking of changing your car or taking it to the mechanic soon? If the answer to all these questions is a yes, then you are on the right page!

But before we start, we want to assure you that you don’t need to panic or get stressed about the fact that your car’s engine power is reduced or it is affected to a state where the check engine light is also on!

what causes reduced engine power light to come on
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The reduced engine power causes can vary, so there is no such fixed reason why your car engine power is reduced.

There can be two completely different reasons for two different cars for such an issue, and that is why it is important that you know almost all the probable causes of reduced engine power problems.

Beyond that, you must also know how to fix the reduced engine power issue without being panicked and, of course, at an affordable rate. It is understandable that the continuous flash of the message “Engine Power is Reduced” might as well frustrate you, but that will never solve the problem.

That is why, in this comprehensive guide, we have discussed what causes reduced engine power warning light to come on, what is the actionable solutions to fix the issue, and all other relevant details about the same. So, do not waste more time and start reading the entire article now.

What Does Reduced Engine Power Mean?

Before we move on to know what causes engine power to reduce and how to fix the problem, we must know what does it mean when engine power is reduced or when these warning signs are flashed on your vehicle’s display.

In most cases, when such a warning sign is flashed, or when you detect that the engine power is reduced, it’s because the vehicle’s primary computer, also known as PCM or Powertrain Control Module, detects a system failure and automatically reduces the power of the engine.

When you notice that the engine power is reduced or any such message is flashed on display, you should know that there might be some fault in the engine’s system causing the trouble.

Mostly there might be some underlying concern leading the engine to reduce power, but you should be able to check for the exact cause to fix it so that your engine performance is not compromised.

You may wonder what does it mean when car says engine power reduced? Well, it means your car engine needs some fixing before it starts running properly again. The car acceleration rate may slow down, and in worst cases, the PCM may even cut off the fuel delivery to the car engine, which will cause the car to stop.

While these warning lights and messages are reason enough to know that there is a fault in your car engine system, it is important that you know the proper answers to what causes reduced engine power light to come on and how to fix it as well.

But there is nothing to worry about; keep reading, and you will know everything in this guide.

You might also like to know: What to Do When Check Engine Light Comes On?

What Causes Reduced Engine Power and How to Fix It?

Whenever you see the “Engine Power is Reduced” warning light comes on in your vehicle, it’s a clear sign that something is wrong. The problem could be due to various reasons, such as a clogged air filter, a malfunctioning sensor, or some issues with the fuel system.

But don’t worry; we have got you covered. Here, we’ll explore all the common causes of the reduced engine power warning light and discuss what you can do to fix it in the best ways possible.

We’ll also share practical and helpful tips on how to check your air filter, inspect your fuel system, and seek help from a professional mechanic if needed. So, without any further ado, let’s learn what causes engine power reduced warning light to come on and how to fix it quickly and easily. Here we go:

Loose Wire, Clamp or Damaged Harness

One of the most common causes of why the reduced engine power warning light turns on is this one – a loose wire, clamp, or a damaged harness. we all know that our car engine system has numerous wiring and electrical connections that make the car run properly.

A short circuit in these electrical wires or any damage in the clamp or harness can lead to a non-functioning car, which may flash the reduced power engine message on the car display.

This is often the most common reason why there is a sudden reduced engine power issue on the car. It is also the easiest to recognize as well. And when you know the cause, you should also know how to fix engine power reduced warning message.

Obviously, the most coveted fix to this issue is to reconnect the loose wire or repair the damaged harness. But before you try this stunt, make sure you disconnect the vehicle’s battery first. Because when you are dealing with the car’s electrical system, it can be dangerous if the battery is connected.

If you are unable to fix the loose wires and reconnect them, do not take a chance and call a car mechanic to do the job. However, if the problem is not in the electrical system, check for the other causes mentioned next!

Bad or Failing Oxygen Sensor

This is another of the most common reduced engine power causes you need to know. A bad or failing oxygen sensor might not only show the reduced engine message or switch on the check engine light, but if it’s not treated on time, it may also lead to dangerous problems in your car that you may regret later.

The car’s oxygen sensor works toward measuring the amount of oxygen that exits the car through its exhaust system. It aids in adjusting the air-fuel mixture of the car engine to maintain proper combustion. And when there is a fault in any of the sensors, the check engine light or engine power reduced light will be turned on.

However, do not panic; there is always a way out of every problem, and fixing this is also easier. The best to do when there is a faulty oxygen sensor issue is to clean it.

Yes, perhaps the engine power is reduced message flashes because of a clogged oxygen catalytic converter. And when you clean it properly, the system will get cleared and start working properly again.

In most modern vehicles, there are two oxygen sensors; in some, there can be up to eight, so finding which one is causing the problem is also a task you should carry out. If, even after cleaning, it doesn’t work, you may need to replace it. The cost of replacement can be within $500, including labour costs.

ECU Malfunction

An ECU malfunction is one of the most complex and costliest issues your car may face when there is a reduced engine power issue. Generally, what causes engine power reduced is a failure in the car’s electrical system.

The ECU, or the Engine Control Unit, is the source of all such electrical connections in the car. It is the computer with which all the major sensors of the vehicle communicate, and it also controls almost all major operations running in the car’s engine system.

In unusual conditions, it also compensates for any faults or problems in the engine. And when there is a faulty ECU, it can switch on the check engine light and flash the reduced engine power message.

As already mentioned, it’s one of the costliest issues of the car, and you need to fix it as soon as possible. The best way to fix this problem is to replace the unit because, unfortunately, it is kind of a computer system that you probably cannot repair.

That is why buying another unit is advised. However, when your car says reduced engine power, and there is a problem in the ECU of the vehicle, do not take the responsibility of fixing it alone. Take the help of a professional and get it fixed by him.

Bad Throttle Position Sensor

Another very significant reason why your car says reduced engine power is a bad throttle position. Well, for those who do not know, a throttle position sensor is located near the throttle body that allows air into the car engine by opening up.

When you step on the accelerator pedal, the sensor measures the position and tells the computer system how much to open the valve. When the valve is opened correctly, it will allow a proportionate amount of air into the car engine.

The throttle sensor also aids in shifting the transmission when the air enters the car engine. And any problem in this position can lead to non-communication with the computer system, which can eventually turn the reduced engine power light on. To fix this issue, it’s better to change the throttle and buy a new one.

Unlike replacing the ECU unit, this one is not a costlier fix. A new throttle body sensor can cost you anywhere between $100 and $500 depending on the brand you prefer.

And if you are too good at mechanics, you might be able to replace it yourself. However, if you don’t have knowledge about fixing car issues, it is advised that you call a car mechanic who knows how to fix reduced engine power issues inevitably!

Clogged Catalytic Converter

If you are still wondering what causes reduced engine power warning light to turn on, here is another reason you must know! The car’s catalytic converter is placed underneath the car right after the exhaust manifold.

Its work is to convert harmful carbon monoxide into carbon dioxide through the process of oxidation and reduction. This helps reduce the harmful emission by the car, which, in turn, helps keep the environment safer.

Currently, in the US, it is illegal to drive a car that doesn’t have a catalytic converter. And if the car has a clogged catalytic converter, it will fail the emission test. This will put on the reduced power engine light, and on top of that, upon finding out, you may be fined too.

So, when the catalytic converter is clogged or not working properly, your car’s engine will not be able to convert the carbon monoxide into carbon dioxide, which will lead to polluting the environment.

Thus, if you have been wondering- why my car says engine power reduced, this could be one prominent reason. To fix this, of course, you need to clear the clog.

If the clog is beyond repair, then you need to replace it. And this, like the ECU, is a costlier issue. You may have to shell out $2000 approximately for the replacement, including labour and parts.

Faulty Mass Air Flow Sensor

A faulty mass air flow sensor is one of the important reasons for reduced engine power in your car. The airflow sensor is located between the intake manifold and the air filter of the car’s engine system.

It works towards measuring the air density, pressure, and other similar things that enter the car’s direct injection engine.

Basically, it commands the computer on how to mix the incoming air with the fuel and deliver it in a way so that proper combustion occurs within the engine. So, it is evident that faulty mass airflow sensors will stop all this work, which will lead to the reduced power of the car engine.

So, what to do when your engine power is reduced due to a faulty mass air flow sensor?

You can fix this problem by cleaning the mass airflow sensor off any dust or debris that might have clogged its pathway. You can also get some sprays on the market that do the job well.

If the problem persists even after cleaning, you might have to replace the sensor, which can cost a few hundred dollars, including the labour cost.

Issues With the Throttle Body

Are you still wondering- why does my car says engine power reduced? Well, any issue in the throttle body might be another cause to look out for. A throttle body has more to it than just a throttle sensor we discussed earlier in the list.

There is a butterfly valve that opens and closes within the throttle body that, allows air to enter the car engine. And when there is an issue in this valve, like it’s broken or damaged, it can turn the reduced power engine light on.

Also, if there is carbon build-up in the engine, it may clog the opening and closing of the valve, which in turn can also switch on the warning light as the system might think there is less air being received.

While all these can lead to reduced engine power, there is always a way to fix it! And if you are thinking of repairing each part of the throttle, then you are probably thinking wrong.

It is so because it is better to replace the entire throttle than to just repair each part, not only in terms of expense but also with respect to the work you need to do to replace each part.

And replacing the entire throttle will cost you only around $100-$200, depending upon the make and model of the car. So, before you question yourself, why is my reduced engine power light on? Check for issues in the throttle body.

Car Battery Problem

If you are still thinking about what causes reduced engine power, then consider the car battery problem to be another good reason for the problem.

Generally, the car doesn’t show too many signs when there is a battery problem, and even the engine power reduced light also doesn’t get turned on initially, which is why it is difficult to detect a car battery problem.

No matter whether it is a damaged, dead, or broken battery cell, the light won’t turn on. If there are other problems with the battery, only then can you expect the engine power-reduced light to turn on.

So, if you had this question in your mind – can a bad battery cause reduced engine power?

The answer is, of course, yes, but finding the fault is the key. The basic fix to this problem is ensuring all the battery connections are well in place and not corroded or completely damaged.

And if there is corrosion, you must clean it after disconnecting the cables. You can use baking soda or other cleaners for this purpose.

Sometimes charging the battery is all you might need, while sometimes you may need to replace the battery if the condition is too bad and it is not too expensive also!

Transmission Failure

All these while, you have read about all the possible sensors in your car while we were discussing what causes reduced engine power light to come on. All these sensors are intertwined by correct transmission operation. And failure in the transmission will lead to the power engine light to put on eventually.

When there is a transmission fault code in the system, it will lead to reduced engine power. The reason behind such failure can be a slipping clutch or low transmission fluid. When you detect the cause, it becomes easier to fix it.

If there is low transmission fluid, you can easily check it yourself while subjected to the owner’s manual. Sometimes the problem can be solved by replacing the transmission fluid entirely.

But if the problem is not this, something severe might be going on that needs a professional’s attention. It is better to consult an auto mechanic in such cases as they know better what causes reduced engine power light to come on and how to fix it in the most convenient way.

In addition, they might also be able to detect the actual fault in the transmission.

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Is It Safe to Drive with Reduced Engine Power Light On?

Often most car owners wonder whether it is safe to drive with reduced engine power lights on. Well, as already discussed above, the reason why your car display shows the reduced engine power message is because there is some fault either in the engine system or the battery.

The other significant reduced engine power causes are also mentioned above, and some of these are majorly dangerous if not treated on time. However, if the problem is minor, driving with reduced engine power light on is still fine unless you will be like that for a longer period.

And most times, though, the problem is minor only. But, if you detect some major cause behind the reduced engine power warning light getting turned on, it suggests that you get it fixed first and then take your vehicle out.

Driving the car with the warning flashing is not recommended when the problem is major. It can potentially harm your car and cause issues like an electrical fire, seized engine, etc.

So, the answer to the question – can you drive with reduced engine power light on, might be a yes if the problem is minor and no if the problem is major.

Must check: What is the Best Oil Additive to Stop Engine Knocking?

How Much Does It Cost to Fix Reduced Engine Power?

There is no exact answer to the question – how much does it cost to fix reduced engine power? It is so because the cause behind the problem differs for different cars, and thus the fixing cost will also vary accordingly.

For instance, if the problem is in the oxygen sensors or there is a loose wire or damaged harness, the cost will not be too much. You can expect to pay anywhere around $100 to $500 for such minor fixes, which includes the labour charge and the cost of the parts as well.

However, the reduced engine power repair cost increases when the servicing is major. If there is a problem in the catalytic converter of the car engine, then you can expect to pay around $2000 to fix it.

In most cases, the cost also increases depending upon the type of auto shop you are choosing for the repair. But overall, if you want to know how much does it cost to fix a car with reduced engine power light on, find the cause of the problem first and then figure out the cost!

What Causes Reduced Engine Power Light to Come on and How to Fix It?

By now, you have become familiar with what causes engine power-reduced problems in a vehicle and the probable solutions to fix them. The problems or causes behind reduced engine power discussed in this article are the most common ones found to date.

But it is not always possible to check for all the causes one by one to be sure of the actual problem in your car, isn’t it?

So, first, you need to check for a few things in priority when you see the reduced engine power warning light getting turned on! If you ask me which these priority checklists from among the causes mentioned here, I would suggest starting with the following three:

  • Loose Wire, Clamp, or Damaged Harness (the most common cause)
  • Clogged Catalytic Converter
  • Bad or Failing Oxygen Sensor

So, when you wonder why is my reduced engine power light on, you must root for checking these three problem-causing areas. If there is no problem with these three parts, you may check the other parts.

And the best solution to fix these problems is already discussed above, so you can fix your reduced power engine issues instantly after you successfully find the cause behind them. Hopefully, this article has helped you understand what causes reduced engine power warning light to come on and how to fix it quickly and easily in the best ways possible.

Don’t let the engine power is reduced warning message stress you out; try out these actionable solutions to fix the issue and get back on the road quickly. Drive safely and avoid costly repairs.

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About Jace Cuban

I am an automotive enthusiast who loves to be around cars and pickup trucks. Applying innovative car care products and installing different latest car accessories are my hobbies. Also, I love sharing my adventurous experience with car lovers.

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