Your Request for Help

Your name *Your contact phone *Your contact emailYour message

Select your make

Select auto repair shop

Your preferred contact Info

Issues

Your concern might be complex to diagnose and may require additional equipment to pinpoint the cause. In this case, you'll receive Digital Inspection results plus a quote to perform deeper diagnostic/test procedures.

Home / Symptoms / Reduced Engine Power Light

Four common causes for a reduced engine power warning on the vehicle and their related parts.

If you are short on time and want to fast-track the process to professional help, clickYes

Are You Experiencing a Reduction in Your Car's Engine Power?

The reduced engine power light appears because the vehicle has limited its power output based on a problem it has detected; this is a designed safety measure. This is caused by issues with the fuel pump or catalytic converter. Alternatively, faulty sensors might be triggering this.

Watch out: Trust us; it's better to catch these things early on before they become big problems. Not only will it save you time and money, but it'll also give you peace of mind on the road. Spot the early warning signs of reduced engine power and take action before symptoms worsen.

Let's Get To The Bottom Of It!

Has your vehicle's power worsened?

The fuel pump is an electric device inside the gasoline tank that pumps a specific amount of fuel to the engine. However, if it stops working properly, the engine may not receive enough fuel, resulting in a loss of power.

In addition you may notice the check engine light on the dashboard, fuel economy decrease, engine underperformance, or engine stumbling.

Is the vehicle unresponsive when you press the accelerator pedal?

The engine control module connects your car's gas pedal and throttle body. The pedal has sensors telling the computer how fast and swiftly the driver presses the pedal. The computer then uses this information to open or close the throttle body's plate. There are also sensors in the throttle body that measure the throttle plate's position. If these sensors or the wiring fails, the computer activates the check engine light and limits the car's performance for safety. This makes the vehicle feel unresponsive when you press the gas pedal.

If you notice the vehicle idling high, cranking and not starting, the engine stuttering, or underperforming, save this information; they're essential if you go to an auto shop later.

Is your check engine light on?

The ECM (Engine Control Module) is the brain of the engine and powertrain. It controls the engine's air and fuel flow and cylinder firing time. The ECM uses input from sensors on the vehicle to make these decisions. If the ECM receives correct inputs but doesn't send the right outputs, the check engine light activates, and the car may underperform. For example, if a coil driver, which sends signals to the coils, fails, it causes a cylinder misfire, activating the check engine light.

If you notice the vehicle shuddering, losing extra fuel, limited to certain speeds, the engine stuttering, or underperforming, save this information; they're essential if you go to an auto shop later.

Is your vehicle taking longer to accelerate?

The catalytic converter is a part of the exhaust system that helps reduce emissions. It has precious metals that help reduce pollutants when the engine runs correctly. However, the catalytic converter can clog and overheat if the engine is not running correctly, like getting low oxygen or too much fuel. This can restrict the exhaust flow, leading to power and acceleration loss. The vehicle may also feel sluggish.

If you notice the engine stalling, long cranking time, poor power when merging on a highway, low fuel mileage, or the check engine warning light on the dashboard, save this information; they're essential if you consider going to an auto shop later.

Is your car idling high?

The throttle body is a part of your car's engine that controls the amount of air that goes in. The car's computer controls it, but there's also a part that helps to set a proper idle speed. If either this part or the throttle body gets clogged with gunk, your car underperforms, sometimes making the idle too high.

If the throttle plate position is wrong, the engine control computer sets a fixed limp mode, triggering a reduced engine power warning light.

It is important to take note of any symptoms like a high engine idling, long cranking time, shuddering, the need to hold the throttle open to start the vehicle, speed limitations, or a decrease in fuel mileage. This information will be useful if you visit an auto shop later.

Is your vehicle hesitating under hard acceleration?

The mass air flow sensor sits in the intake before the throttle body. It measures the amount of air coming into the engine, helping the car's computer calculate how much fuel and engine load gets good performance. However, if this part gets dirty, it can give false readings, causing the car to hesitate when accelerating or not accelerate at all.

It is important to take note of any symptoms such as engine stalling and not starting, cranking for an extended period, the vehicle shutting off, speed limitations, poor performance, or a decrease in fuel mileage. This information will be useful if you visit an auto shop later.

The most common causes for a reduced engine power light

The most common causes for a reduced engine power light are:

Throttle pedal sensor malfunction: The throttle pedal sensor measures how much the driver is pressing the accelerator. This sensor can fail and send wrong information to the vehicle’s computer. The information from these sensors helps the car understand what kind of situation the driver is in to decide whether to activate safety systems, etc. Therefore, if the sensor sends wrong information that the driver is flooring the pedal, the engine might reduce power as a safety measure in some vehicles.
Throttle body issues: The throttle body controls the amount of air going to the engine. So, when you press the accelerator the throttle body opens up, allowing more air inside the engine, helping performance. However, the throttle body can become so dirty that its valve gets stuck, causing bad airflow and reducing engine power.
Faulty engine control module: The engine control module receives information from many sensors, components, cylinders, etc., regarding the vehicle’s performance. However, the control module itself can develop internal failures. For instance, even though a cylinder might be working fine, the engine control module isn’t processing its information due to faulty wiring.
Weak fuel pump: The fuel requires hydraulic pressure and pumping to reach every component and part it needs; this ensures the engine’s combustion works efficiently. However, if the fuel pump fails, the engine stops receiving proper fuel amounts, resulting in a lower engine performance which can trigger a warning light on the dashboard.
Clogged catalytic converter: The catalytic converter is a vital part of the vehicle’s emission system, being a passageway that filters vapors and gases. However, if the catalytic converter clogs up, the gases and vapors that need to go through the converter can build up inside the engine. This accumulation of hot vapor and gas causes overheating and bad airflow in the engine, resulting in low engine power.
Faulty mass airflow sensor: The mass airflow sensor measures the amount of air getting into the engine. The sensor is vital to control the engine’s performance so the engine knows what air amount it’ll work with. However, a faulty mass airflow sensor can’t provide the necessary information so the engine knows how to work efficiently, causing low engine power.

Find Professional Help

Please select your vehicle's brand and location so we can locate the best professional help for you

Brand of your car

Your location

If you are a shop owner and sick of business directories that are based on the cost of repair, AutoTechIQ is for you. If your customers receive Digital Inspection results then AutoTechIQ is definitely for you. Check out the certification page or how to rank in your area.

Frequently Asked Questions

Has your vehicle's power worsened?

The fuel pump is an electric device inside the gasoline tank that pumps a specific amount of fuel to the engine. However, if it stops working properly, the engine may not receive enough fuel, resulting in a loss of power.

In addition you may notice the check engine light on the dashboard, fuel economy decrease, engine underperformance, or engine stumbling.
Is the vehicle unresponsive when you press the accelerator pedal?

The engine control module connects your car's gas pedal and throttle body. The pedal has sensors telling the computer how fast and swiftly the driver presses the pedal. The computer then uses this information to open or close the throttle body's plate. There are also sensors in the throttle body that measure the throttle plate's position. If these sensors or the wiring fails, the computer activates the check engine light and limits the car's performance for safety. This makes the vehicle feel unresponsive when you press the gas pedal.

If you notice the vehicle idling high, cranking and not starting, the engine stuttering, or underperforming, save this information; they're essential if you go to an auto shop later.
Is your check engine light on?

The ECM (Engine Control Module) is the brain of the engine and powertrain. It controls the engine's air and fuel flow and cylinder firing time. The ECM uses input from sensors on the vehicle to make these decisions. If the ECM receives correct inputs but doesn't send the right outputs, the check engine light activates, and the car may underperform. For example, if a coil driver, which sends signals to the coils, fails, it causes a cylinder misfire, activating the check engine light.

If you notice the vehicle shuddering, losing extra fuel, limited to certain speeds, the engine stuttering, or underperforming, save this information; they're essential if you go to an auto shop later.
Is your vehicle taking longer to accelerate?

The catalytic converter is a part of the exhaust system that helps reduce emissions. It has precious metals that help reduce pollutants when the engine runs correctly. However, the catalytic converter can clog and overheat if the engine is not running correctly, like getting low oxygen or too much fuel. This can restrict the exhaust flow, leading to power and acceleration loss. The vehicle may also feel sluggish.

If you notice the engine stalling, long cranking time, poor power when merging on a highway, low fuel mileage, or the check engine warning light on the dashboard, save this information; they're essential if you consider going to an auto shop later.
Is your car idling high?

The throttle body is a part of your car's engine that controls the amount of air that goes in. The car's computer controls it, but there's also a part that helps to set a proper idle speed. If either this part or the throttle body gets clogged with gunk, your car underperforms, sometimes making the idle too high.

If the throttle plate position is wrong, the engine control computer sets a fixed limp mode, triggering a reduced engine power warning light.

It is important to take note of any symptoms like a high engine idling, long cranking time, shuddering, the need to hold the throttle open to start the vehicle, speed limitations, or a decrease in fuel mileage. This information will be useful if you visit an auto shop later.
Is your vehicle hesitating under hard acceleration?

The mass air flow sensor sits in the intake before the throttle body. It measures the amount of air coming into the engine, helping the car's computer calculate how much fuel and engine load gets good performance. However, if this part gets dirty, it can give false readings, causing the car to hesitate when accelerating or not accelerate at all.

It is important to take note of any symptoms such as engine stalling and not starting, cranking for an extended period, the vehicle shutting off, speed limitations, poor performance, or a decrease in fuel mileage. This information will be useful if you visit an auto shop later.

Typical fixes to address the cause(s)

These are typical processes and repair services that fix a check engine light issue

The most common cause: Weak fuel pump

The most common reason for a car's low engine power light is a weak fuel pump. A vehicle’s fuel pump has a motor that gives it power so it pumps fuel, increasing hydraulic pressure. This way, the pump ensures enough fuel gets to the engine during the combustion process. However, a pump can fail, and is a common reason for the engine to have combustion issues including a low power status.

Symptoms it causes: Apart from the low power engine light, you might notice engine stalling, misfires, bad fuel economy, etc.
High risk of priority: The fuel pump is vital for the engine’s combustion process. If the pump is faulty, your fuel economy worsens and the engine is prone to damage. In worst cases, the engine might stall or even suffer major breakdowns.

How exactly does the fuel pump fail?

A fuel pump can fail due to natural aging, which happens at around the 100,000 - 150,000 mile range. However, the fuel pump might also suffer damage depending on driving conditions, other combustion issues that overstress it, running on low fuel frequently, and accidents.

Go safe: Ask for a mechanic to inspect your vehicle’s fuel system to investigate if the fuel pump is failing due to surrounding components and if there’s further damage to check out. Many shops do transparent vehicle inspections and lay out your options after investigating your vehicle’s conditions.

What’s a vehicle inspection? It’s “detective work” on your vehicle, checking its systems to see if anything prevents the car from working as expected. In this case, mechanics examine different parts of your vehicle to track if anything is causing the fuel pump to fail. They’ll also check the condition of components during their inspection, noting which are causing the problem and which got affected by it, recommending to replace them in order of priority.

Transparency example in a weak battery service

A fuel and combustion system inspection is the most transparent process to understand why your vehicle’s fuel pump is faulty. This is because many components surrounding the fuel pump and combustion system components can have a say in the issue, indicating the real culprits that caused it all.

Let’s read an example of how this kind of inspection helps to service a faulty fuel pump, fixing a reduced engine light problem.

A customer brought their vehicle to the shop, reporting it felt weaker to move. The vehicle seemed hesitant, and the customer thought it might need a tune-up.

During a test drive, the technician noticed that the check engine light was on, and the vehicle was slightly sluggish and hesitant when accelerating.

The technician did a vehicle health inspection and ran a diagnostic code scan. They found a code that indicates "system too lean" on bank 1. However, no other issues were found related to the customer's concern. So, the customer approved additional tests.

During additional tests, the technician used a specific scanner, discovering that the bank one fuel trim was not lean at idle. So, the computer tried adding fuel while the vehicle was running. This indicates a malfunctioning fuel pump.

The technician tested the fuel pressure using a mechanical pressure gauge, discovering it was well below the specified level. Plus, it had a blocked return line, which indicated a failing fuel pump. The technician recommended replacing the in-tank fuel pump and retesting the vehicle.

Weak fuel pump

In this case, the mechanic put the “Immediate Action” tag on the fuel pump.

Similar Symptoms

Below are just a few examples of typical Symptoms and Fixes your car might be experiencing

Batteries can develop damages, become weak, or run out of power, preventing the vehicle from starting.