What Do Reduced Engine Power Mean?

When this light appears, most of the time users get confused and don’t know what to do when the reduced engine power light turns on mean?  Because it comes at different times and situations, however, it clearly shows that something is faulty with the engine.

To guide you in dealing with this confusing scenario, we will explain what the reduced engine power alert means. We also investigate the reasons for this engine warning and estimate the cost of repair.

One of the most prevalent reasons for this problem, however, is a fault with your vehicle’s electronic throttle actuator control (TAC) system. Many contemporary vehicles use this layout instead of a traditional, mechanical throttle body and connection.

The ECU manages two accelerator position sensors in a throttle actuator control system to identify your intent to accelerate. The device then uses two throttle position sensors to compute the optimum throttle response. After gathering the essential information from the sensors, the ECU employs an actuator motor to direct the airflow into your car’s engine.

The lower power may hinder the car from shifting and accelerating. In severe circumstances, the PCM will limit gasoline to the engine, resulting in a car that will not start.

This system is also referred to as the fail-safe mode. However, it is often referred to as the limp mode since the warning allows you to drive home without inflicting more harm to the engine or transmission.

What is Fail-Safe Mode?

The warning “engine power decreased” indicates that your car has entered a fail-safe mode. To safeguard drivers, all modern vehicles are outfitted with a fail-safe method.

Your vehicle’s ECU may activate a fail-safe mode to either safeguard the persons inside or to prevent additional harm to the vehicle. When your automobile is in fail-safe mode, your vehicle’s internal electronics might limit its performance in a variety of ways. For example, if the electronic throttle actuator fails, the electronic control unit may reduce the maximum throttle opening. If your vehicle’s gearbox is faulty, the electronic control unit may restrict transmission operation to a certain gear range.

Some vehicles may display a dedicated message on the dashboard to alert you that they are in fail-safe mode. In some cases, your “Check Engine” light may illuminate.

Trouble Codes Associated with Reduced Engine Power

A specific issue code will show in the electronic control module’s (ECM) memory depending on the type of car you possess and the problem detected by the ECU. Some of these error codes include:

A specific issue code will be stored in the memory of the electronic control module (ECM). Some of these error codes may include:

  • P0120-P0124: This code indicates an issue with the pedal or throttle position, or with the circuit.
  • P1125: This code denotes a malfunctioning system or component and varies based on the make and model of your car.
  • P1518: This code indicates a broken system or a bad system component, and it may differ based on the make and model of your vehicle.
  • P2111: Indicates that the throttle actuator control system has been jammed open.
  • P2135: An issue with the accelerator pedal position (APP), the throttle position (TP) sensor or switch, or the A/B voltage correlation.

Taking your car to a local service shop and having it inspected by a trained technician is the best approach to properly diagnose and fix it.

Here are the reasons behind What Do Reduced Engine Power Means?

If the low engine power indicator flashes, take your vehicle in for a diagnostic. It might be as simple as changing the air filter, or it could be something more serious.

The reduced engine power warning light comes on for different reasons:

  1. Circuit issues
  2. Faulty throttle and pedal position sensor
  3. Defective Oxygen Sensor
  4. Malfunctioning ECU
  5. Failing Mass Airflow Sensor
  6. Transmission Failure
  7. Clogged Catalytic Converter
  8. Engine Oil Level is Low
  9. Faulty Distributor
  10. Worn or Faulty Spark Plugs

1.  Circuit issues

What Do Reduced Engine Power Mean?

Damaged wires and improper connections hinder the TAC (Throttle Actuator Control) system from functioning correctly. This condition can cause a variety of issues with a vehicle, including entering the limited engine power mode.

While a loose connection is usually straightforward to replace, it isn’t always easy to locate. To detect the flaw, you would need to conduct a thorough investigation of the systems.

2.  Faulty throttle and pedal position sensor

The low engine power warning light can appear if there is an issue with the TAC system. One of the most prevalent causes is the presence of one or both APP sensors in the accelerator pedal, as well as a pair of TP sensors.

The throttle body comprises various components that might fail and cause these alerts. First, the butterfly valve is in charge of allowing air into the engine. When this valve fails, the required amount of air is not delivered.

Carbon can also accumulate around this valve, causing it to malfunction. When the engine doesn’t get enough air, it will misfire and splutter, resulting in dashboard alerts.

3.  Defective Oxygen Sensor

What Do Reduced Engine Power Mean?

Oxygen sensors are required to determine how much O2 is leaving the system through the exhaust. The ECU will change the air-fuel ratio to balance performance if there is too much or too little oxygen flowing out.

A malfunctioning sensor, on the other hand, might give inaccurate information back to the computer, causing incorrect changes to be made. This causes an imbalance in the air-fuel combination, which not only results in poor performance and engine problems but can also cause the Reduced Engine Power Warning to appear.

Related: What Does A Car Do When The Oxygen Sensor Is Bad?

4.  Malfunctioning ECU

What Do Reduced Engine Power Mean?

The Engine Control Unit is the operation’s central processing unit. All of the sensors connect with the ECU to allow necessary changes to be performed. If the air-fuel combination isn’t appropriate, the ECU changes what’s going on to improve performance.

However, when the ECU begins to malfunction, a variety of problems might arise. You may begin to notice the poor performance when the engine adjusts for faults that may or may not exist.

5.  Failing Mass Airflow Sensor

The mass airflow sensor is located between the intake manifold and the engine air filter. Its duty is to monitor the density and pressure of the air entering the engine.

When these measurements are completed, the data is delivered to the ECU so that the right fuel ratio may be applied. When the MAF sensor malfunctions, erroneous data is supplied, causing difficulties with the ratios and triggering warning lights.

6.  Failure of Transmission

Transmission problems are never easy to deal with and may cause a lot of problems. You should expect to see certain error messages if the transmission is sliding or the fluid level has dropped.

While most people do not associate a decrease in engine power with gearboxes, the two systems are strongly intertwined. If none of the other suspects are to blame, it is time to investigate the transmission.

7.  Catalytic Converter Blockage

The catalytic converter is located after the exhaust manifold. The primary function of this critical component is to transform hazardous exhaust gases into less hazardous pollutants. The catalytic converter might become blocked if the engine hasn’t been functioning correctly or as the car ages.

When this happens, the car not only fails an emissions test, but it also has certain engine performance concerns. The Reduced Engine Power Warning will not always be illuminated, but the Check Engine Light will be illuminated at the very least.

8.  Engine Oil Level is Low

If your oil level is low, your engine power light will be on, indicating that your vehicle requires extra oil. This is quite unsafe for a variety of reasons, so take the automobile to a repair and have them check your oil level. They can top off your oil if it is below the safe limit.

9.  Faulty Distributor

If your distributor is faulty, it can cause engine power light illumination on your dashboard. You would need a new distributor and possibly other parts like spark plugs if they were affected by your faulty distributor to fix this issue.

10. Worn or Faulty Spark Plugs

Most automotive specialists believe that if your spark plugs are worn out or damaged, the engine power light on your automobile will illuminate. To avoid this, you should get the spark plugs replaced as soon as possible.

Other considerations

The decreased engine power alert might potentially indicate that your vehicle is running excessively lean or rich. This might be due to a filthy air filter, vacuum leaks in hoses, or a clogged fuel line (or something else preventing fuel flow).

So What to Do when Reduced Engine Power appears?

This question has a simple answer: you have it diagnosed and addressed right away. Taking it to a professional technician can expedite the process since they can immediately diagnose the problem and recommend a solution.

If you’re driving and the low engine power warning light illuminates, don’t worry. It’s not the end of the world, but you should definitely stop somewhere safe and call your mechanic before continuing.

How much does it cost to fix reduced engine power?

The cost of restoring engine power will vary depending on the severity of the problem. The reduced power problem is usually small and costs around $100 to fix in a workshop, but in severe situations, combining time and components, it can cost up to $100 to $800.

Using an engine code scanner should help you narrow down the location of the problem. The OBDII scanner will read any problem codes and show you which systems are at issue.

Final Verdict:

Ideally, you would detect a loose connection that would be free to repair if you could re-establish the link. However, changing the catalytic converter or swapping out the ECU may be an expensive remedy that would send your car to the junkyard.

Never drive with the Reduced Engine Power Warning light illuminated. If the Limp Mode is engaged, you must immediately drive to a safe spot and switch it off. Turn on your danger lights to alert other vehicles that you are experiencing mechanical difficulties.

It is suggested that you have the vehicle towed if you have more than a few miles to drive. You don’t want to be stuck on the side of the road or in an accident.

Recommended to be inspected by an expert mechanic.

Frequently Asked Questions:

Is It Safe to Drive with Reduced Engine Power?

When the check engine light turns on, most engines do this. It is your vehicle’s “limp home mode.”

When this happens, it’s important to remember that the engine won’t generally go past a certain speed, which is important whether you’re on the freeway or interstate. You leave as soon as possible. Motorways feature both a minimum and maximum speed restriction.

If you get off the mentioned highway, look for a service station right away; if that isn’t feasible, attempt to find a location to pull over and phone for help.

Avoid driving with the check engine light on or travel the shortest distance feasible.

Can a bad battery cause reduced engine power?

In most situations, a battery problem, such as a dead/damaged cell or a loose ground, will not light the reduced engine power light.

How To Bypass Reduced Engine Power?

To bypass the reduced engine power you have to fix the issues causing your engine to have reduced power.

Can a bad alternator reduce engine power?

Not really: The lighting of the battery indicator on the dashboard is the first sign of a damaged alternator. If your battery light does not illuminate after starting, your alternator is in good working order. Check your brakes if you see your car losing revs.

How do I reset my reduced engine power light?

There is only one solution to clear the low engine power light: fix the underlying problem. The low engine power indicator usually turns off after a specific amount of driving time.

About The Author

Avatar for Ibrar Ayyub

Ibrar Ayyub

I am an experienced technical writer holding a Master's degree in computer science from BZU Multan, Pakistan University. With a background spanning various industries, particularly in home automation and engineering, I have honed my skills in crafting clear and concise content. Proficient in leveraging infographics and diagrams, I strive to simplify complex concepts for readers. My strength lies in thorough research and presenting information in a structured and logical format.

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