BMW Engine Malfunction Reduced Power – What Are The Causes?

BMW engines are highly efficient, dependable, and powerful. It truly is among the best available.

Despite its excellent performance, the motor is not without flaws. One of the common problems is BMW engine malfunction reduced Power.

When the DME module in a car detects a problem, the iDrive display shows the Reduced warning Power caused by a malfunction.

This issue may also result in the appearance of the Check Engine light.

Because some difficulties might cause this notice or warning, it’s critical to acquire a precise diagnosis before beginning repairs.

What Does Engine Malfunction Reduced Power BMW Mean?

BMW Engine Malfunction Reduced Power

If you observe a decreased power alert in your BMW owing to an engine problem, it signifies that the performance of your car has been purposely restrained.

This restriction arises because the automobile computer enables this warning signal if a system malfunction or low performance is detected. This option inhibits the car from speeding up.

Reduced engine malfunction BMW indicates that the vehicle is not generating full output at a particular engine RPM or is not running at the desired level.

If the engine runs at a higher or unusual RPM, the pistons are most likely not moving to the appropriate degree of engine power.

The reduced engine power mode is sometimes referred to as ‘limp home mode.’ It’s a safety feature provided by vehicle manufacturers to avoid additional harm to the transmission or engine.

When you try to accelerate your car, it decreases acceleration or fails to reach a particular speed due to diminished engine power.

Also, if you are driving and the automobile suddenly begins to slow down, this denotes a loss in engine power. It illustrates that the engine is running inefficiently and produces less power.

Engine malfunction BMW can occur in a variety of ways.

The most prevalent is a vehicle that does not receive enough gasoline. The engine control system of the car may malfunction.

What Causes BMW Engine Malfunction Reduced Power?

BMW engine malfunction reduced power is due to problems in the following parts:

  • Valvetronic
  • Vanos
  • Oxygen Sensor
  • Ignition Coils
  • Timing Chain
  • Battery – Loose Connection
  • High-Pressure Fuel Pump (HPFP)
  • Turbo
  • ECU
  • Transmission

Despite its impressive showing, the engine BMW reduced Power is a typical issue with BMWs.


BMW created Valvetronic, a unique mechanism that allows for variable valve timing. The variable intake valve lift offers the driver with precise and consistent control.

Valvetronic systems often operate with a separate VANOS system to continually modify the duration of the exhaust camshafts and intake.

Rather than using a butterfly valve, the engine manages load regulation by valve lift.

You’ll notice a loss of power and potentially a lack of throttle responsiveness when it fails. As the system is so intricate, there are several problems.

In this case, you must inspect each one individually.However, shaft orientation and electric motor sensors are the most common causes of engine malfunction reduced power indication due to motor failure.

If you own an OBD-II scanner, check the Valvetronic fault codes to define the problem.


The VANOS is controlled by the oil-powered gearboxes in the engine block when running a BMW.

It’s a basic design for longevity, but it might be defective if too much scale accumulates within the solenoid coils.

The most typical trigger of this problem is that the vehicle does not adhere to the regular maintenance routine.

While washing and oil replacements are beneficial, solenoids are more prone to failures beyond 70,000 miles.

When you encounter this issue, you will likely notice a power decrease due to engine malfunction.

You may notice knocking or grinding noises from the engine when idle or driving.

Oxygen Sensor

BMW uses upstream oxygen sensors to produce measurements that enhance engine performance.

It’s normal to see a power loss owing to an engine failure notice on the iDrive display when things don’t perform as intended.

The most prevalent culprit of these sensors failing to function properly are excessive oil or fuel use. Loose connections or wire damage are also possible.

When the oxygen sensor malfunctions, you may see a yellow engine light.

Ignition Coils

Ignition Coils

A faulty ignition coil can happen for many reasons. When this arises, a misfire is frequently the result, which can cause significant harm to the catalytic converter.

When you accelerate, your BMW may shake, especially if the pedal has been pressed to the floor.

Timing Chain

Timing belts in older automobiles often wear out after 100k to 150k miles. To increase endurance, the new BMW versions have switched to a chain.

It is designed to last the engine’s life. However, faults or damage might occur.

Some chains will weaken their links after extended usage, resulting in the engine malfunction reduced power BMW x5 warning sign.

The tensioners or plastic guides may also be broken, causing the device to leap three or more teeth.

The most typical indication of a timing chain failure is a rattling engine noise emanating from the vehicle.

Battery, Loose Connection

A power decrease due to engine failure notice may display on the iDrive screen if your BMW battery is not provided with sufficient power to satisfy the vehicle’s demands.

As batteries deteriorate, they lose energy. Replacement is necessary to keep the system operational when a specific threshold is achieved.

But the issue may not come from the battery only. If the charging system isn’t working, the automobile will behave similarly.

High-Pressure Fuel Pump (HPFP)

High-Pressure Fuel Pump

The HPFP system is a complicated mechanism that can be harmed if a vehicle is powered by low-grade gasoline.

When you get a power decrease warning because of an engine problem, the fuel pump or injectors are frequently the culprits.

This issue makes the vehicle cycle longer and more vigorously before starting. You may notice difficult idling and yellow engine malfunction light.


Several problems can lead turbines to cease performing properly. It might be induced by a faulty vacuum line, solenoid coil, or a break in the tube connecting the intake manifold with the intercooler.

Rubber hose clamps frequently slide or break, allowing the hose to become disconnected. Replacing them can often solve the problem.

You might have an open exhaust or a valve leak producing acceleration issues.


The motor controller is the operation’s central processing unit. All sensors interact with the ECU for necessary changes to be performed.

If the air-fuel mixture isn’t correct, the ECU alters the process for improved performance.

When the ECU begins to malfunction, though, any issue can emerge. You may notice poor performance as the engine resolves matters that did not arise.


Transmission problems are inconvenient and are one of the BMW x5 engine malfunction reduced power problems.

Several error codes may appear if the transmission slides or the fluid level is low.

While many believe the drop in engine power has no relevance to the gearbox, the two systems are inextricably linked. It is time to investigate the transmission if there are no other suspects.

How To Do A BMW Check Engine Light Reset?

You can proceed with the reset if your BMW check engine light is illuminated but not encountering any of the above mentioned issues.

Here are the easy procedures for resetting the BMW check engine light:

  • Turn off the engine and put on your safety accessories.
  • Find the negative terminal. It often features a black cap and a negative sign (–).
  • Remove the side’s connector from the battery by loosening the screw on the negative terminal using a tool. Please put it on hold for a minute.
  • Reattach and secure with a wrench.
  • You may also do a BMW check-light reset by unplugging the battery system, but you’ll also need to reboot your car’s infotainment system.


Can I Fix An Engine Malfunction Reduced Power Warning?


While seeing the Reduced Power Warning might be frightening, the remedy is typically quick and uncomplicated. It could be the result of a broken connection.

When you have the Diagnostic OBD-II Scanner to scan the error codes issued by the DME module, you can make the right decision since you have all the information you need.

If you are unclear about how to replace or fix a specific item, find a mechanic or speak to your local BMW dealer about the present warning or caution light.

How Much Does Reduced Engine Power Warning Repair Cost?

To get your engine going again, you should budget between $100 and $500, including components and labor. On the other hand, the catalytic converter issue might cost more than $2,000.

Can I Drive With Reduced Engine Power?

Yes, but not recommended.

If you’re on the drive and the low engine power alert light turns on, don’t worry. It’s not risky, but you should certainly stop and call a service center before driving.


In conclusion, the article above lists the common problems of BMW engine malfunction reduced Power.

To ensure your vehicle performs the best, you should check it and have it repaired if there are any issues.

Thank you for reading this post.

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