Drivetrain Malfunction on a BMW: What Is It and What to Do?

Drivetrain Malfunction on a BMW: What Is It and What to Do?

If you’re here, you’re probably dealing with a drivetrain malfunction on your BMW.

In this guide, we will discuss what this malfunction means and what steps you can take to fix it.

So, let’s dive in.

Quick Answer: What is a drivetrain malfunction on a BMW?

A drivetrain malfunction on a BMW indicates that there’s an issue with the car’s engine, transmission, driveshaft, or differential. It is often highlighted by a warning message on the iDrive screen. The most common causes are old spark plugs, faulty ignition coils, or a malfunctioning fuel pump.

What does the drivetrain do in a BMW?

In your BMW, the drivetrain is the system that connects the engine’s power to the wheels. It’s composed of the engine, transmission, driveshafts, and differential.

When there’s a drivetrain malfunction, a particular component disrupts this system.

The BMW Digital Motor Electronics (DME) system can detect this disruption. It will record the issue and activate a safety feature known as “limp mode.”

This mode is like your car’s way of saying, “I need to slow down and protect myself.”

When in limp mode, your BMW limits its own performance to prevent further damage.

For instance, it caps the top speed to around 40 mph and might restrict the engine’s power output.

This allows you to drive to a safe location or a service center, but it’s a clear signal that your car needs immediate attention.

Symptoms of a BMW drivetrain malfunction

Here are some common signs that indicate a BMW drivetrain malfunction:

  • Check engine light. This is one of the most straightforward indicators that something is amiss with your vehicle. If the check engine light illuminates, it’s a signal to check your car’s diagnostic system for error codes that can pinpoint the issue.
  • Drivetrain warning message on the iDrive Screen. A drivetrain warning message here is a direct alert that your vehicle’s drivetrain needs immediate attention.
BMW drivetrain malfunction message on iDrive screen
  • Lack of power. If you notice that your BMW isn’t accelerating as it should or feels less responsive, it could be a sign of drivetrain trouble.
  • Misfires. You might notice the engine sputtering or hesitating, which can lead to uneven power delivery and a rough driving experience.
  • Rough idling. This rough idling can be due to various issues, including misfires or other engine troubles.
  • Car shaking. Apart from rough idling, you might feel the whole car shaking, especially at certain speeds or when shifting gears.
  • The engine shuts down during idling or after putting the car into drive (D). If your BMW’s engine unexpectedly shuts down while idling or soon after shifting into drive, it’s a significant indicator of a drivetrain malfunction.
  • BMW won’t start. A car that doesn’t start can have various causes, but when combined with other symptoms on this list, it could be related to a drivetrain issue.
  • Thick smoke from the exhaust. Unusual smoke from the exhaust, especially if it’s thick and colored, can be a sign of severe internal issues, possibly related to the drivetrain system.

What causes a drivetrain malfunction on a BMW?

A BMW drivetrain consists of hundreds, if not thousands of parts. Therefore, a drivetrain malfunction can also have lots of different causes.

The best way to determine the exact cause is by using an OBDII reader to check the exact fault codes. (We will cover this in the next section.)

However, there are a few causes that are most common for BMW drivetrain malfunctions:

  • Old spark plugs. Over time, spark plugs can wear out or get fouled, leading to misfires, reduced power, and drivetrain stress. BMW spark plugs should be replaced every 30,000 miles.
Fauled spark plugs example
  • Faulty ignition coils. If you have faulty ignition coils, you’ll likely experience misfires, loss of power, and a lit check engine light. BMW ignition coils generally last for at least 140,000 miles, but they can go bad earlier.
  • Faulty fuel injectors. When the fuel injectors malfunction, they disrupt the engine’s air-fuel ratio, leading to poor combustion and power loss. Some BMW fuel injectors last for over 150,000 miles, while others start malfunctioning (much) earlier.
  • Malfunctioning fuel pump. A malfunctioning pump can’t maintain the proper fuel pressure, leading to engine and drivetrain issues due to inadequate fuel supply. A BMW fuel pump can start malfunctioning at any mileage as it’s not part of preventative maintenance.
  • Clogged catalytic converter. If the catalytic converter is clogged, it can cause increased backpressure, reducing engine efficiency and potentially causing drivetrain problems due to restricted exhaust flow. A BMW catalytic converter should last for at least 10 years.
  • Cold weather. Extreme cold can affect your BMW’s drivetrain components, making fluids thicker and movement more strenuous, which can exacerbate existing issues or highlight weaknesses in the drivetrain system.
  • Low-quality fuel. Using substandard fuel can lead to deposits in the engine and fuel system, potentially causing drivetrain malfunctions due to poor combustion and residue buildup. For most BMWs, it’s recommended to use premium gas.
  • Low battery voltage. Your BMW’s electronics, including those managing the drivetrain, rely on a stable power supply. Low battery voltage can disrupt these systems, leading to a drivetrain malfunction. A healthy BMW battery should read around 12.6 volts or above when the car is turned off.
Low-voltage battery illustration

How do you fix a BMW drivetrain malfunction?

The best way to fix a BMW drivetrain malfunction is to use an On-Board Diagnostics II (OBDII) tool.

This tool reads fault codes from your BMW’s DME and provides specific insights into what’s going wrong. An example of such a tool is OBDeleven:

OBDeleven diagnostics tool full scan results

Here’s a step-by-step guide on how to use an OBDII tool to diagnose and fix a drivetrain malfunction:

  1. Connect the OBDII tool. First, locate your BMW’s OBDII port, usually found under the dashboard near the steering column. Plug in the OBDII scanner to establish a connection with the vehicle’s computer system.
  2. Read the fault codes. Once the OBDII tool is connected, it will scan the vehicle’s computer system for any stored fault codes. These codes are generated when the system detects a malfunction in the drivetrain.
  3. Interpret the fault codes. Each fault code provides specific information about the nature of the problem. For example, a code like “P0303” indicates a misfire in cylinder 3. The tool often provides a brief description, but you may need to refer to a BMW fault code list for a more detailed explanation.
  4. Diagnose the issue. Based on the fault code, you can identify the component that’s causing the problem. For instance, if the code points to a misfire in a specific cylinder, the issue could be related to spark plugs, ignition coils, or fuel injectors.
  5. Fix the issue. Once you’ve pinpointed the problem, the next step is to address it. If the issue is with an old spark plug or a faulty ignition coil, replacing the defective part might resolve the problem. For example, if the fault code indicates a problem with the ignition coil in cylinder 3, you would replace the faulty coil with a new one.
  6. Clear the fault codes and test drive. After fixing the issue, use the OBDII tool to clear the fault codes from the system. Then, take your BMW for a test drive to ensure the issue is resolved and the drivetrain is functioning correctly.

How much does it cost to fix a BMW drivetrain malfunction?

The cost of fixing a BMW drivetrain malfunction can be anything from $100 to $5,000+, depending on the specific issue and the model of your BMW.

For instance, replacing faulty spark plugs is generally one of the more affordable fixes.

The cost for new spark plugs can range from $10 to $30 each, depending on the type and brand, plus labor, which can vary based on the garage’s rates and your vehicle’s accessibility.

For a BMW, you can expect the total cost for replacing spark plugs to be in the ballpark of $100 to $300, depending on the number of cylinders.

A row of firing spark plugs - illustration

On the other hand, addressing a clogged catalytic converter is a more expensive repair. The catalytic converter itself is a costly component, and the price ranges from $1,000 to over $2,500, not including labor.

With labor costs included, the total repair might exceed $3,000, especially if additional parts like oxygen sensors need replacing during the process.

FAQs about a drivetrain malfunction on a BMW

Here are some common FAQs about BMW drivetrain malfunctions:

Is a drivetrain malfunction covered under BMW warranty?

Yes, a drivetrain malfunction is covered under BMW’s Powertrain warranty for up to 4 years or 50,000 miles.

Can you still drive with a drivetrain malfunction?

Generally, you can still drive with a drivetrain malfunction, but it’s not recommended. Driving your BMW when a drivetrain warning is present can lead to further damage. If your car goes into limp mode, it’s best to drive it only as far as necessary to get it to a safe location or a repair facility.

How long is a BMW drivetrain warranty?

The BMW drivetrain warranty lasts for 4 years or 50,000 miles, whichever comes first. This coverage is standard for new BMWs, but if you’re purchasing a used BMW or your initial warranty period has expired, the coverage details may vary.


Whether it’s a simple spark plug replacement or a more complex repair like fixing a catalytic converter, addressing problems early is always the best approach.

If you ever feel unsure, don’t hesitate to consult with a professional to keep your BMW running smoothly.

Drive safely!

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