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Duramax Reduced Engine Power (How To Reset)

Since 2001, Duramax has been a powerhouse in diesel engines. They’re incredibly popular and can be found in a range of General Motors vehicles.

Most owners swear by them. But sometimes, this powerhouse engine slows down and starts flashing an ‘Engine Power Reduced’ message. There is a way to do a Duramax engine power reset, but first, you should check for any underlying problems.

To do a Duramax engine power reset: turn off the ignition and wait 5 seconds, then hold down the ‘trip odometer’ reset button and turn the ignition on, keep holding the odometer button until the change engine oil message is displayed, then release the button and turn the ignition off. 

There are a few ways to do an engine power reset on a GM vehicle. Some are simple, and others can be complicated, but with the info in this article, you should be able to do one yourself.

Always remember, though, if you run into any problems, you should consult a professional mechanic or take your vehicle to a dealership to be checked out.

How To Do A Duramax Engine Power Reset

Once the problem has been found and fixed, you will need to do an engine power reset. Some Duramax enthusiasts and mechanics simply disconnect the engine’s battery and reconnect it. Once reconnected, the engine automatically resets and clears the engine power management system.

Try this if you want, but in some cases, it may not reset the engine power light.

If you can’t get to the battery or would like to follow a more formal method, you can follow these steps:

  1. Put the vehicle into neutral with the handbrake on.
  2. If the ignition is on, turn it off and wait 5 seconds.
  3. Hold down the ‘trip odometer’ reset button and turn the ignition on.
  4. Keep holding the odometer button until the change engine oil message comes on the display.
  5. Release the button and turn the ignition off.

This should manually reset the power management system and clear any warning codes. The warning light should no longer be displayed.

Always remember, if the warning light comes on again or the vehicle still doesn’t have enough power after the reset, you should send it in for a full diagnosis with a mechanical professional.

The powertrain control module in the vehicle has detected a system failure somewhere that needs attention. The module has intentionally reduced the vehicle’s performance to protect the engine.

Why Does A Duramax Engine Lose Power?

Even though the Duramax engine is one of North America’s most popular diesel engines, that doesn’t mean they can be without their problems. 

Sometimes, a fault, blockage, or wear and tear can cause the engine to lose power. In some cases, you can fix the problem yourself, but often, you will need to take it to a professional mechanic.

In most cases, you’ll still be able to drive it with the reduced power and warning light, but you shouldn’t drive it more than about 50-80 miles. This range should be enough to get it to a mechanic ASAP or home if necessary. Reduced power and a warning light are a big warning that something is potentially wrong.

There are two common reasons a reduced power warning light will appear on your display:

  • There is a fault in the engine, which is causing it to lose power.
  • There is a loose or faulty sensor in the engine that is sending a false signal about the engine’s power output.

In a few cases, the cause of the power loss is something as simple as a loose connection in the engine. In other words, the warning light is on, but nothing is being damaged.

But sometimes, the warning light comes on because it is something serious:

  • Low engine oil levels.
  • A clogged filter.
  • Dirty or faulty fuel injectors.
  • Other malfunctions that can cause damage to the engine.

You should never ignore a warning light because you never know which it is.

When there is a fault in the engine, the most common causes are a problem with the ECM (engine control module), dirty or clogged fuel filters, or a faulty fuel injector.

When a sensor is the problem, it is often the mass airflow sensor or the throttle position sensor that gives trouble. In some cases, there is a problem with the engine’s computer, which gives false information even though there isn’t anything physically wrong.

Should the mass airflow sensor be faulty, it will incorrectly adjust the amount of air entering the engine, which could reduce power.

Similarly, if the throttle position sensor is not working properly, it will tell the engine to supply too much or too little diesel to the engine.

Whether the problem is with a sensor or the engine is actually producing less power than it should, you have to get it repaired, or you could damage the engine further and rack up some very expensive repair bills.

When Should You Do A Duramax Engine Power Reset?

As part of an engine diagnosis, you’ll do an engine power reset to clear any previously stored codes and allow the various sensors in the vehicle to tell you if there are specific areas to check.

But there are at least five instances where you’ll do an engine power reset:

  1. The engine power warning light has come on, and you have resolved the issue.
  2. The vehicle has been in an accident and is being repaired.
  3. You have tuned the engine or replaced the fuel filter or injectors.
  4. You have replaced a sensor in the vehicle, such as the throttle position sensor or the mass airflow sensor.
  5. A DTC (diagnostic trouble code) has been cleared, but the light is still on.

There are other reasons to do a Duramax engine power reset, but the list above should cover most scenarios.

Take Note: Clearing the warning light will not automatically fix the problem. If there is a mechanical fault or a physical issue like clogged filters and injectors, clearing the warning light will still leave your vehicle with less power than it should have. Always look for the underlying problem and fix it before clearing the warning light.

Helpful Tips When Doing A Duramax Engine Power Reset

If you are diagnosing the problem yourself, there are a few things you can do to make the process easier and quicker.

The most obvious is to read the owners-manual. It is usually the last resort for most people, but the information is there for a reason, and it could actually save you some time.

If you’ve read the owners-manual, there are also a few practical ways to ensure the reset goes smoothly:

  • Check that the vehicle is in park or neutral before you start the reset process.
  • The order of the reset process is important, and doing the steps in the incorrect order will cause the reset to fail. Follow the steps in order.
  • Be sure to hold the odometer reset button until the change engine oil message appears on the display. If the change engine oil message doesn’t appear, you must restart the process.


Duramax engines are incredibly popular, but sometimes, they lose power and flash a warning light. The good news is that a Duramax engine power reset is easy and often only takes a few minutes.

Be careful; the warning light is there for a reason, so always diagnose and fix the underlying problem.