If the “Engine Power Reduced” warning comes on your dashboard, consider it your engine’s cry for help, signaling that something isn’t right.
But what exactly triggers this warning?
Read on to understand the meaning of the “Engine Power Reduced” message and the common faults that can set it off. We’ll also explain how to diagnose and fix this issue.
This Article Contains:
- What Does “Engine Power Reduced” Warning Mean?
- 8 Common Causes That Trigger the “Engine Power Reduced” Warning
- How to Diagnose and Fix “Engine Power Reduced” Warning
- 4 FAQs about the “Reduced Engine Power” Warning
What Does “Engine Power Reduced” Warning Mean?
A “Reduced Engine Power” or “Engine Power Reduced” warning means your engine isn’t working at full capacity. This alert is triggered when your car’s computer detects an issue in the throttle, fuel, emissions, or other critical components.
When the light comes on, vehicles go into “limp mode” — a protective state that reduces engine power, limits the transmission to lower gears, and restricts RPMs to protect the engine.
So, what problems can illuminate this warning light?
Let’s find out.
8 Common Causes That Trigger the “Engine Power Reduced” Warning
Here are some common problems that can cause this dashboard warning light to appear:
1. Throttle System Problem
If your vehicle’s computer notices any of these throttle-related issues, it can trigger the warning light:
- Throttle body problems: A dirty or faulty throttle body can disrupt airflow, leading to reduced engine performance.
- Faulty throttle position sensor: When one or both Throttle Position Sensors (TPS) fail, your car or truck may enter reduced engine power mode.
- Accelerator Pedal Position Sensor (APPS) failure: If the APPS fails, it won’t send proper signals to the Engine Control Unit, resulting in reduced power output.
- Circuit issues: Damaged wires or poor connections can disrupt the throttle system’s function, potentially triggering the reduced engine power light.
2. Fuel System Issues
Fuel system issues can lead to inadequate fuel delivery, reducing engine power. This typically happens due to a malfunctioning fuel pump, clogged fuel filter, or faulty fuel pressure regulator.
3. Emission System Issues
Problems in the emissions system can cause the engine to lower its power to meet emission limits. These can be due to:
- A faulty catalytic converter: A clogged catalytic converter restricts exhaust flow, reducing engine performance.
- Failed O2 sensors: These sensors monitor the engine’s air-fuel ratio. If they fail and provide incorrect data, you’ll notice poor acceleration, increased emissions, and reduced engine power.
- Exhaust Gas Recirculation (EGR) valve issues: A stuck or clogged EGR valve can disrupt the air-fuel mixture, causing reduced engine performance.
- Mass Air Flow Sensor failure: A faulty sensor can misread air flow, leading to improper air-fuel mixtures and reduced engine power.
- Clogged Diesel Particulate Filter (DPF): DPF is an exhaust system component in diesel vehicles that removes soot particles from the exhaust gas. A clogged DPF makes the engine work harder to push out the gasses, reducing efficiency.
4. Electrical System Problems
Electrical problems prevent the engine from receiving the power it needs to operate efficiently. Common causes include:
- Faulty alternator: A failing alternator can’t supply sufficient electricity to power the engine and other components, potentially causing engine power reduction.
- Low battery voltage: A weak battery struggles to provide enough energy to the engine’s computer (ECU), resulting in reduced power.
- Loose wire connections: Loose clamps and damaged wires can interrupt the electrical flow to the engine components and accessories, impacting their performance.
5. Cooling System Issues
The cooling system is vital for maintaining the engine’s optimal temperature. If the coolant levels are low or there’s a leak, the ECU may activate the reduced engine power light to prevent overheating and damage.
6. Malfunctioning Engine Control Unit (ECU)
The ECU manages engine functions, including fuel injection, ignition timing, and emission controls. When it malfunctions, the ECU can send incorrect signals or fail to manage these functions properly, causing the engine to enter limp mode to prevent further damage.
7. Transmission Failure
The transmission system relies on multiple sensors and components to operate smoothly. However, a faulty sensor, slipping gears, or transmission fluid leaks can disrupt its function.
When the transmission system detects a problem, it may limit the vehicle’s speed and gear options to reduce engine power.
8. Ignition System Problems
Bad spark plugs and ignition coils can disrupt the engine’s ability to burn fuel and air properly, causing a misfire. This can trigger the “Reduced Engine Power” warning.
Next, let’s see how you can clear this light.
How to Diagnose and Fix “Engine Power Reduced” Warning
Diagnosing and fixing the “Reduced Engine Power” warning can be complex since it can appear for multiple reasons, so it’s best to consult a professional mechanic for help.
Here’s how a mechanic will diagnose and fix the issue:
1. Check for Diagnostic Trouble Codes (DTC): Your mechanic will use an OBD-II scanner to identify the cause of the problem.
Some common error codes that can come up are:
- P0101: Shows up when the MAF signal sent to the Engine Control Module is irregular or out of the expected range.
- P0700: This code is triggered when the Transmission Control Module (TCM) detects a problem with the automatic transmission controls.
- P2135: Indicates issues with the throttle position sensor or its voltage correlation, often due to failures in the throttle or accelerator pedal position sensor.
- P2195: Appears when the oxygen sensor detects insufficient fuel or inaccurate fuel trim values in the system.
2. Replace faulty components: If they find any defective parts within the engine system, such as the throttle body, sensors, fuel injectors, etc., they’ll perform a replacement. They’ll also check and replace a faulty alternator or battery.
3. Clean clogged parts: The mechanic may clean a clogged fuel filter or replace a dirty air filter to resolve the problem.
4. Reset the computer: If the warning light persists after repairs, the technician will reset the vehicle’s computer using an OBD diagnostic tool or by temporarily disconnecting the car’s battery.
Curious to know more about this light?
Keep scrolling.
4 FAQs about the “Reduced Engine Power” Warning
Here are answers to common queries a car owner may have about this warning light:
1. What Are the Symptoms of Reduced Engine Power?
Besides the “Reduced Engine Power” warning, several other indicators can signal engine power issues in a car or truck, including:
- Illuminated Check Engine Light
- Unresponsive gas pedal
- Poor acceleration
- Vehicle jerks or stalls
- Unusual noises coming from the vehicle
- Decreased fuel efficiency
2. Can You Drive in Reduced Engine Power Mode?
While you can technically drive to a repair shop, it’s not advisable to drive long distances.
Your car or truck enters reduced power mode to prevent engine damage, and continuing to drive can worsen the issue. Instead, it’s recommended you tow your car to a repair facility.
3. Can You Clear the Warning Light Yourself?
No, you shouldn’t. Simple fixes like replacing a dirty air filter might be easy, but complex issues like fixing emissions or electrical system faults require advanced diagnostic tools.
That’s why it’s better to have a skilled mechanic resolve these issues effectively.
4. How Much Does Resolving “Reduced Engine Power” Issues Cost?
The cost to resolve “Reduced Engine Power” problems varies depending on the faulty components that need replacement and the labor rates.
Here are some estimates (including labor):
- Air filter: $190 to $270
- Mass airflow sensor: $230 to $350
- Spark plugs: $250 to $500
- Throttle position sensor: $250 to $500
- Fuel injector: $500 to $2,500
- Transmission (manual and automatic): $1,500 to $5,000
Say Goodbye to Engine Woes with AutoNation Mobile Service
As a car owner, understanding the “Engine Power Reduced” warning triggers and getting timely repairs can help you save time and money.
For a hassle-free experience, call the experts from AutoNation Mobile Service to diagnose and fix reduced power mode issues.
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