Reduced Engine Power Light: Meaning, Causes, & Fixes

Tim Miller
Reduced Engine Power Light


Your engine’s performance is reduced.

Reduced Engine Power Light


  • Clogged or Faulty Throttle Body
  • Malfunctioning Sensors
  • Electrical System Issues



Easy to fix


What Does the Reduced Engine Power Light Mean?

reduced engine power light

When you turn on the vehicle, the reduced engine power light illuminates briefly as part of a system check. After a few seconds, the light should turn off, indicating normal function.

However, if the reduced engine power light stays on or illuminates while you drive, it indicates a problem with your engine’s performance. You should have your car diagnosed and repaired as soon as possible.

To efficiently diagnose the issue causing the reduced engine power light, consider utilizing a scan tool. Think of it as your car’s health checkup – it connects with your vehicle’s systems, reads trouble codes, and helps pinpoint the problem.

Is It Safe to Drive With the Reduced Engine Power Light?

Yes, driving with the reduced engine power light can be safe for a short distance as long as you take precautions and drive carefully.

However, it is not recommended to drive for an extended period of time, as this may cause further damage to both your safety and the engine. Your vehicle’s computer system will limit the engine power output, making it more difficult to accelerate or maintain speed. This can increase the risk of accidents, especially when driving at high speeds or in heavy traffic.

What Causes the Reduced Engine Power Light to Come On?

1. Clogged or Faulty Throttle Body
clogged throttle body

The throttle body regulates the airflow to the engine. If there is an issue with the throttle body, it will affect engine performance and trigger the warning light.

2. Malfunctioning Sensors
The engine’s throttle system includes various sensors that monitor its performance, such as:

  • Throttle Position Sensor (TPS) measures the position of the throttle valve.
  • Manifold Absolute Pressure Sensor (MAP) measures the pressure of the air entering the engine.
  • Mass Air Flow Sensor (MAF) measures the amount of air entering the engine.
  • Accelerator Pedal Position Sensor (APP) measures the position of the accelerator pedal.

If any of these sensors fail, they can send incorrect information to the engine control module (ECM), leading to issues with engine performance and potentially triggering the warning light.

3. Electrical System Issues
Many car owners wonder if a bad battery can cause the reduced engine power light to come on. The answer is yes. When the battery is weak or dead, the electrical components of the engine may fail.

Additionally, loose, corroded, or damaged wiring can interfere with the throttle’s communication with the vehicle’s computer.

How to Diagnose and Fix the Reduced Engine Power Light

Step 1: Use an OBD2 scanner to identify the cause

As mentioned above, there are a lot of causes triggering the warning light. Once a malfunction is detected, the information related to the malfunctioning components is stored in diagnostic trouble codes. Thus, you need a scan tool to read the codes and identify the cause. Follow these steps to learn how to use an OBD2 scanner:

  • Turn off the engine.
  • Connect the scanner to the OBD2 port. Most scanners have a cable plugging into the port, while others may be wireless.
  • Turn on the ignition.
  • Follow the scanner instructions.
  • Select the “Read Codes” function on the scanner.
  • Figure out what the codes mean by using the DTC Lookup Library on the scanner or going to the OBD2 Codes Lookup to find meaning, causes, symptoms, and how to fix it.

Step 2: Repair the malfunctioning parts based on the codes

Should you possess enough knowledge about cars and the appropriate tools, you can replace or fix the defective part on your own. If not, you might consider taking your car to an auto repair shop.

Step 3: Reset the reduced engine power light

For various reasons, the DTCs may still remain stored in your car’s computer. In such cases, you should use an OBD2 scanner to clear the DTCs completely. Most scanners offer a “Clear codes” function, which can be selected to erase the codes from the computer.

Next, restart your engine and go for 50 – 100 miles. The light will be gone, and the problem will be solved!

What’s Next?

By now, you should have a good understanding of what to do if you encounter a reduced engine power light in your vehicle. 

However, if you’re experiencing additional symptoms or have identified other causes of the problem, share them in the comment section below. This helps us all become better-informed car owners and keep our vehicles running smoothly for years to come.

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Information sourced from the owner's manual.