Does a BMW Engine Malfunction Reduced Power message come on when your car’s engine computer (DME module) detects a problem? When the BMW engine malfunctioning message on your Drive, the check engine light (service engine soon) may also come on.

bmw engine malfunction reduced power x6 due to vanos

The color of the check engine light can help you understand how serious the problem is. BMW Engine Malfunction Reduced Power Problem warning is a common problem that affects BMW models, including 335i, 535i, 745i, X1, X3, and X5.


BMW Engine Malfunction message is shown on the iDrive screen.

BMW owners may notice the following symptoms:

  • Reduced Engine Power
  • Increased emissions
  • Reduced Output
  • Transmission in limp home mode ( in some cases)
  • Drivetrain malfunction and engine light
  • Reduced engine message coming up during acceleration

Common Problems

This list of common problems triggers the BMW Engine Malfunction Reduced Power message. To determine why you are getting this warning, start by reading the fault codes by connecting a BMW scanner to the OBD-II port under the dashboard on the driver’s side.


Most BMW engines are equipped with Valvetronic. It variates the amount of intake valve lift, eliminating the need for a throttle plate.

Although this is quite a complex system, it is quite durable. If it fails, you might have a poor throttle response and a lack of power. The usual failure points are an electric motor and an eccentric shaft position sensor.

Codes: 2A61, 2A63, 2A67, 2A6F, 2A70


bmw engine malfunction reduced power x6 due to vanos

Oil-powered actuators operate Vanos. It is a straightforward and robust system. In most cases, it will fail if there is an oil sludge buildup within the Vanos solenoids. This is a result of too-long oil change intervals. Luckily, faulty Vanos solenoids are an easy and cheap thing to fix.

In addition to the “BMW engine malfunction reduced power” message, you will also notice engine noise such as tapping or knocking (VANOS area). Usually, after starting a cold engine or at idle for the first few seconds.

Codes: 2A82, 2A87

Oxygen Sensor

BMW oxygen sensor engine malfunction sign

BMW engine control uses readings from upstream O2 sensors to achieve optimal engine performance. Upstream O2 sensors can get fouled by excessive fuel or oil consumption.  Furthermore, damaged wiring or a loose connector is also possible. Whatever the reason, it will affect the engine performance, and you will get a yellow 1/2 ‘check engine light.

Codes: 2C9C, 2C9C, or P0171 to P0174

Ignition Coils

bmw engine malfunction yellow light due to loose ignition coil

Ignition coils can fail for many reasons. It will result in a misfire, causing the engine to shake and judder under acceleration.

Misfire damages your catalytic converter, so don’t drive your BMW with a misfire. Ignition coils are easy to replace, so it’s a good idea to have one spare ignition coil. A loose connector to the ignition coil can cause the BMW engine to malfunction yellow light to come on.

Codes: P0300 to P0306

Timing Chain

bmw engine malfunction reduced power 535i

Timing chain-related problems can trigger a ‘check engine light. Although timing chains are supposed to be lifelong items, they can get exclusively stretched with time.  Tensioners or plastic guides can fail, too. Timing that has jumped two or three teeth will cause an engine rattle, a yellow 1/2 ‘check engine light, and Vano’s related codes.

A Red 1/2 ‘check engine light will indicate a bigger timing jump. In either case, please turn off the engine immediately and do not restart it.


bmw engine malfunction reduced power m3

A weak battery can cause BMW Engine Malfunction and Reduced Power messages on the iDrive screen. BMW vehicles are susceptible to voltage, and if the battery is old, it may hold a proper charge.

If your battery is over seven years old, it is time to change it to avoid other electrical issues. A bad alternator regulator can cause similar symptoms, as well.

High-Pressure Fuel Pump (HPFP)

High-Pressure Fuel Pump

Newer BMW vehicles, starting from E90 335i, have engines with high-pressure fuel injection. This is a delicate system that can be damaged by low-quality fuel.

High-pressure fuel pumps and injectors are the usual failure points. Symptoms include engine hard starting with long cranking, rough idle, and a yellow 1/2 ‘check engine light.

In most cases, power output and acceleration are heavily affected. You must check and replace the faulty pump or injectors as soon as possible.

Codes: 2FBA, 2FBF, 29DC, 29E2


bmw turbo triggers engine malfunction warning

You may have a boost leak if you have a turbocharged BMW that feels down and powerful and sluggish on acceleration. This can be caused by something as simple as a broken vacuum line.

Boost solenoids that operate the turbochargers can fail. You should also check the charge piping that connects the turbo with the intercooler and intake manifold. These are rubber hoses that can break or slip off. Lastly, a stuck open wastegate or a leaking blow-off valve will also cause low boost issues.

Codes: 30FF for a boost leak

How to diagnose BMW Engine Malfunction Reduced Power

You will need a BMW Scanner to read manufacturer-specific fault codes to diagnose BMW Engine Malfunction. Pay attention to the DME module’s fault codes and perform a full system scan.

Frequently Asked Questions

My BMW has a big yellow check light and says, ‘Engine fault! Reduced power. What should I do?

If you have this warning, it means there is a serious problem with the engine. It is still OK to drive to your destination, but you should adjust your driving style to ‘moderate.’ A good idea is to pull over at a safe place and look under the hood. Fix the problem as soon as possible. This message can come upon an E60 E70 E90 E92 E65 F10 etc.

What does ‘drive moderately’ really mean?

As the engine is not operating perfectly, you should not put it under a hard load. Avoid harsh accelerations and high engine speeds. Drive gently. Additionally, pay attention to any signs of abnormal operation. Unusual exhaust smoke, engine judder, or high engine temperatures are causes for concern.

My BMW has a ‘check engine light, but I can’t read fault codes.

Some OBD2 readers can read only the mandatory powertrain codes (Pxxxx). BMW is more complex than most cars and has many manufacturer-specific codes. You will need a scan tool capable of reading this code for good engine insight.

We hope you find the BMW Engine Malfunction Reduced Power guide helpful. Check these troubleshooting and repair guides for more help on your BMW.

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  1. Anonymous says:

    Hi there,
    I have exactly the same problem that you mentioned above. Hope you find the solution of it . Can you advice please.

  2. Anonymous says:

    I have a 2008 BMW X6 5.0 or 4.4 V8 twin turbo engine, engine malfunction reduced power keep popping up, than I change all fuel injectors it was running perfectly for 1000km and now the problem is back again, car only did 78k km so far, really frustrating please help

  3. Anonymous says:

    Did u find the problem got the same problem

  4. Anonymous says:

    Thanks for this page.
    Had the 1/2 engine light today and engine felt like it was misfiring. Replaced battery and reset codes all fixed running beautifully.

  5. Anonymous says:

    Check your catalytic converter

  6. Anonymous says:

    Hi it’s sounds like your catalytic converter are block you need to check it with experienced Bmw technician

  7. Anonymous says:

    Hi, I got the half engine symbol today with the mentioned message ( power reduced), the message disappeared when I stopped for 1 hour at a shop and restart the journey again.

  8. Anonymous says:

    I have 2010 BMW problem is engine manfulcition all the starting car smoke to much and run 25 miles for aurs no power very slow running l don’t know

  9. Anonymous says:

    I have 2009 BMW 535i, I just bought it recently, after a week I got 1/2 yellow light check engine with a message on the IDrive say(engine malfunction, power reduced). any advices what the problem might be? note the light goes away after turn off the engine and restarted, but comes on back again after I drive it and exactly when I accelerate.

  10. Anonymous says:

    How much did you spend?

  11. Anonymous says:

    I have a 2011 BMW x5 35d Diesel motor is shaking a lot. Mechanic says those power issues can be glow plugs or injectors it’s also idling low.

  12. Anonymous says:

    I had similar experience a few days ago in my 2013 X5 Xdrive 35d in Bakersfield , California under 100 F. Several problems identified by dealer- 1) low pressure ERG valve faulty, 2) camshaft sensor not reading correctly, 3) glow plug in one of the engine cylinder not functioning properly. Spent a fortune on both parts and labor.

  13. Anonymous says:

    Need some help. Dealer scan and doesn´t really know why it happens. Got X5 xdrive premium 3.0TD, 2011. It gives an engine fault, a yellowish message with half an engine drawing, then it says: full engine power no longer available. Possible to continue journey. Drive moderately. Have the problem checked by the nearest BMW dealer. Problem is, the dealer can´t figure out what the problem is. It got worse when we took it to the beach, here in Costa Rica, the temperatures were at 96F, and that worsen the problem. What it happens is that when I step on it an the revs reach around 3000rpm, it trouble shoots and you can feel the engine actually looses power. When slowing down, then the message disappears and the car keeps running, apparently normally. Except when I tried again to accelerate, it happened again. Does someone knows what the problem might be? thanks.