Home » How Serious Is a BMW Drivetrain Malfunction?
How Serious Is a BMW Drivetrain Malfunction?

How Serious Is a BMW Drivetrain Malfunction?

When everything works correctly, a BMW drivetrain can last for up to 200,000 miles – and often more. If you continue caring for it, the lifespan expectations continue increasing. There are stories of some vehicles crossing one million miles on the original equipment.

That’s not bad, considering older BMW vehicles have a drivetrain warranty of just 48 months or 50,000 miles. You receive a corrosion guarantee of 12 years with unlimited miles.

Most drivers notice problems start creeping into the ownership picture once a vehicle reaches six figures on the odometer. That’s when more repairs tend to be necessary, along with extra proactive maintenance.

If you stay on top of the issues that could develop, the BMW drivetrain malfunction warning isn’t that serious in most situations.

How Serious Is a BMW Drivetrain Malfunction?

The drivetrain malfunction warning can indicate a serious issue, but it is typically not as severe as drivers think when they experience it for the first time. The most common problems that trigger this message are poor fuel quality, spark plug failure, and a loose ignition coil.

If the low-octane fuel, old spark plugs, and loose ignition coils are common causes of a BMW drivetrain malfunction, a problematic fuel injector would be considered an uncommon, but not rare issue that drivers face.

When a drivetrain malfunction occurs because of the fuel injectors, it doesn’t mean a replacement is automatically required. They can be cleaned if clogging occurs, which means a simple flush can restore functionality.

Whenever you have the chance to salvage your fuel injectors, take the opportunity. Replacing this component can be equal to the cost of repairing your BMW’s transmission if you hire someone to do it.

If you’re auto savvy and have some mechanic skills, the Bosch OE Gasoline Direct Injection Fuel Injector can save you plenty on this drivetrain malfunction issue.

Although you’ll need to check for compatibility, it works with the 135i, 328i, 335i, 528i, 535i, 640i, 740i, and X-series models.

Signs and Symptoms of Fuel Injector Failure in a BMW

Fuel injector failure causes four common signs and symptoms, even if the BMW drivetrain malfunction warning doesn’t display.

You’ll notice misfires, harder starts, fewer miles per gallon, and poor engine performance when the injectors stop working as expected.

The fuel injectors fail in two ways. They stop providing as much gasoline as they did, or they begin to deliver too much of it.

With the first issue, the cylinder starts running lean. That creates a hotter temperature and ignition problems, eventually creating a misfire that you’ll feel and hear behind the wheel. If it does start, the engine typically has more vibration and doesn’t operate as smoothly.

If too much fuel gets into the cylinder, you might not achieve ignition because there isn’t enough air available to achieve combustion. This problem often causes those around the vehicle to smell the fuel.

How to Replace the Fuel Injectors in Your BMW

The following steps are applicable to these BMW models and years.

2014-2016 BMW 228i, including xDrive2014-2016 BMW 428i, including xDrive and GranCoupe
2012-2016 BMW 528i, including xDrive2012-2016 BMW 328i, including xDrive and GT
2015 BMW X4 xDrive 28i2012-2016 BMW Z4 sDrive 28i
2013-2015 BMW X1 xDrive and sDrive28i2013-2016 BMW X3, xDrive and sDrive 28i

If you know for certain from an OBD-II BMW compatible scanner or a mechanic’s diagnosis that your fuel injectors are faulty, the following steps can help you replace this essential component at home.

1. Expose the Injectors

The first step is to grip the front of your BMW’s engine cover. Pull it upward to have it pop off where it fastens with the front locating pins.

Once the front pins are disengaged, you can grab the cover’s right side to pull it off the final pin. If you have a BMW from before 2013 that needs the fuel injectors swapped, you’ll have two vacuum lines on the passenger side that must be disconnected before you can have the cover completely removed.

You’ll see a noise reduction pad made of foam underneath the plastic. Pull it upward to remove it from the engine compartment.

Once you’ve reached this point, it’s time to rotate the plastic fasteners on the cowl to remove the rivets. This activity exposes your BMW’s strut brace. You’ll need to remove two plugs from the center of the rear cowl to find the firewall mounting bolts.

Pull the rubber strut covers off, use a ratchet to remove the bolts, and remove the brace. A plastic rivet in each corner of the cover must also be removed.

After that, the cover sitting below the brace must be removed. It has seven bolts to take out with a ratchet and a 10 mm socket. Once you reach this point, you’re ready to proceed to the second step.

2. Disconnect the Wiring

When you look at a BMW’s engine, you’ll see that each cylinder has three components: a ground wire, an ignition coil, and a fuel injector. You’ll need to lift the locks on the coils, unplugging the harness for each of them. Once that is accomplished, you can pull them up to remove them from the cylinder head.

An 8 mm socket is necessary to remove the nuts securing the ground wires to the valve cover.

Next, you’ll need to disconnect the VANOS plug. It’s the large, round connector you can see in the valve cover’s middle. Push on the tabs, then pull up.

A flat screwdriver can help you open the clip that secures the valve cover wiring, allowing the plug and harness to be folded away from the engine.

Under the VANOS is the high-pressure fuel pump. You’ll need to disconnect it from the wiring harness.

Once you get to this stage, the wiring for the fuel injectors can be safely disconnected. Since the space is tight, you’ll need to pry back on the injector where the harness plug connects with a flat screwdriver or something of similar size and sturdiness.

3. Remove the Fuel Injectors

Before you can disconnect the fuel lines, there’s a bracket that you’ll need to move at the back of your valve cover. Remove the bolts, and it’ll be possible to push it out of the way.

Next, you’ll need a 17 mm wrench to disconnect the high-pressure feet. There is fuel in the lines, so you’ll need plenty of rags to prevent a huge mess.

Follow the line from the pump to the rail, disconnecting both ends so that it can be removed from the engine.

You’ll disconnect the low-pressure line next, which sits right beneath the one you just removed.

After that, you can loosen the lines from the fuel injectors with a 14 mm wrench. More fuel will come out as you’re working on this step.

You’ll see four fasteners mounting the fuel rail to the valve cover. These need to be removed so that the rail can be set aside. Once that part of this step is accomplished, you’ll need a 10 mm socket to take out the bolts with the hold-downs.

When you reach this point, it is safe to remove the fuel injectors from your BMW. Use the removal tool and place it on the valve cover with the same orientation as the hold-downs.

The DP Tool Store offers a kit compatible with multiple engine styles, including the N54 and N55, to ensure you complete this part of the job successfully.

The fuel injector tool can pull or install them using reverse thread screws, which makes the work a lot easier. With the DP Tool kit, you’re adding a product made from steel and aluminum for durability that comes with a 12-month warranty.

After you have the tool connected with the injector, thread the brass pieces through the girdle. They need to go into the top of each injector. It helps to leave everything loose until everything is secured.

If you’ve done everything correctly, the injectors pull out by the brass pieces when backing them out.

4. Install the New Injectors

When you look at the side of the injector, you’ll see a specific calibration number printed there. That information is what the computer uses to understand how much gasoline to send its way.

These numbers can be different for each new fuel injector. You’ll need to write them down somewhere and indicate their placement in the compartment.

Once you have that information noted, it’s time to install the decoupler rings onto the injectors. Slide the seam side onto the component, pushing on it until it snaps into place. After that, you can place the injector into the cylinder head.

Drive in the mounting bolts with a 10 mm socket, but first start the threads by hand to ensure the connection is secure. The injectors are fully seated, so keep going back and forth between the bolts, evenly pressing them until they’re in all the way. At that point, you can add torque with your ratchet.

Continue the process in reverse from the removal process until you get to the point where it’s time to put the VANOS plug back over the valve cover.

5. Connect the Electrical System and Code the Injectors

Once the VANOS plug is plugged in, you can connect the injector connectors to the fuel pump. The coils need to be refit to the spark plug tubes, and then you can plug them in as before. Then slid the wires over their studs and thread on the nut to ensure they’re secured. An 8 mm socket tightens the assembly.

At this point, you should have successfully reconnected everything to your engine. If you have a 2012 or earlier BMW, don’t forget about the vacuum lines that run to the engine cover.

Place the cover over the engine to reconnect the lines if necessary for the vacuum lines, then get a scanning tool to use.

It would be best if you had a high-end tool to code the injectors. An OBD-II scanner won’t get the job done. I highly recommend using the Autel Scanner MaxiCOM MK808 for this task. It’ll let you get into the computer to finish the recoding work.

Start by turning the ignition on for your BMW. After plugging in the MK808, you should see a service option appear. Choose that menu option, then pick the injectors selection.

You’ll need to select the automaker next to let the tool read your VIN. Once it has that information, you’ll find several vehicle parameters to review. You’ll need to give the MK808 permission to speak with the computer.

Once the readout is ready, choose the “Hot Function” and then the quantity compensation feature for the injectors.

At this stage, the tool rereads the computer, giving you the codes from the injectors you just removed. You’ll need to navigate to the option that lets you enter new adjustment values.

Once you get there, enter the cylinder that requires an adjustment and the injector code you wrote down for later reference. After entering all the information for each one, save the values.

You can now start the vehicle. It helps to be at the engine bay quickly (or have help) in case fuel comes from the fittings. If any appear, shut down the vehicle and fix the issue before finalizing this update.

When there aren’t any leaks in the system, you can refit the plastics and foam components in the engine compartment.

Is Every BMW Drivetrain Malfunction Serious?

BMW drivetrain malfunctions require a thorough inspection to determine the severity of the issue. Multiple error codes or part failures contribute to this issue, which is why a complete review is necessary.

The first time I replaced a spark plug, I thought it would be easy. I was out there with my tools, maybe 15 years old, helping my uncles work on an old BMW.

After I loosened the one that I was working on, I went to install it a little quicker than I should have been moving. My foot slipped on the gravel, I smashed the part into the engine block, and that ruined the gap.

If the plugs were performance iridium ones, I might understand why they got so upset. These were OEM parts from the local auto shop they bought on clearance for five bucks.

Some teens might have walked away from that situation, vowing to never work on vehicles again. Not me. I was determined to show them I was better than all of them combined.

The information I’ve learned during that journey is often shared here to help you fix the problems you encounter with your vehicle. It isn’t easy to change fuel injectors in a BMW, but it is possible. When you have the right parts and tools, there’s nothing that can stop what you’re capable of accomplishing.

Not even a little gravel.


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