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.
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.
Symptoms
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.
Valvetronic
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
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 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
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
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.
Battery
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)
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
Turbo
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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