Causes for BMW transmission malfunction (Top 7)

In this brief guide, we are going to provide you with the causes of  BMW transmission problems and what you can do to rectify these problems before they worsen.

According to the consumer reports in 2020, BMWs are considered to be averagely reliable. Nevertheless, in this blog, we’ll go through the most common transmission malfunctions that a BMW driver may face.

What causes BMW transmission malfunction?

Most of the common causes for a BMW transmission malfunction are:

  • Overheating
  • TTC clutch failure
  • Gearbox oil is worn out or low levels
  • Mechatronic sensor failure
  • Short circuit or open circuit 
  • Mechatronic sleeves breakage
  • Damaged or worn out solenoids
  • Low battery voltage
  • Torque converter engagement
  • Faulty spark plugs or fuel injectors.

Why does overheating cause a BMW transmission malfunction?

Because transmission gears and shafts tend to get damaged, worn, and malfunction under high heat levels. This results in lower than the acceptable performance from the vehicle and high fuel consumption as well as lowering the life of mechanical components in the gearbox.

What error is shown as a result of overheating?

Generally when a transmission overheats an error P0218 is shown. This error is not immediately visible on the screen but requires a diagnostic tool to get these actual error codes.  

How to fix this BMW transmission malfunction?

After cooling down the transmission check the gearbox oil for its condition. Change it if it is too thick and completely black. Also, check your clutch if it is the problem behind this malfunction.

Why does clutch failure cause a BMW transmission malfunction?

A clutch failure will result in improper disengagement of gears and you will not get the desired drive. A Clutch is a link between the engine and actual transmission. If it is not functioning properly or failing completely then engine power is not transmitted to the wheels.

What errors are shown as a result of Clutch failure?

Error codes such as 1D3101 and 1D3201 are shown by the Bimmerlink app when connected to the vehicle whose clutch is damaged or failed completely. 

How to fix this BMW transmission malfunction?

Repairing the clutch if its friction plates are not too damaged may be the solution to this problem or if the clutch is completely failed then replacing it, is the only option.

Why does a Mechatronic sensor failure cause a BMW transmission malfunction?

This causes an error message on the screen of the transmission and also the BMW goes into a failsafe mode. it also may not start instantly and drive slower than normal

Which errors are shown as a result of this cause?

Error codes 51A7, 2E94, P1717, and 2ADO appear when the engine crankshaft position sensor has a failure in the majority of cases when the cable connecting the sensor to the transmission control unit has come loose. 

How to fix this BMW transmission malfunction?

Make sure that the cable is properly connected to the sensor or the sensor itself is working. These are the ways of fixing this malfunction on a BMW.

Why does a short circuit or open circuits cause a BMW transmission malfunction?

Your transmission functions on electrical circuits and if the circuit is not complete then simply it won’t work. So if there is a short circuit or open circuit somewhere in the transmission then it does not function properly.

Which errors are shown as a result of this cause? 

The set of error codes that a BMW transmission might give are 400626 and 400635 due to short or open circuits. The first error code is related to the turbine speed sensor. The other error is related to the parking lock sensor.

How to fix this BMW transmission malfunction?

The only way to fix these errors is by ensuring the actual sensors are working and cables connected to them complete an electrical circuit. 

Why does a mechatronic sleeve breakage cause a BMW transmission malfunction?

if the mechatronic sleeve valve body is damaged or broken then transmission fluid may leak into the port. As the fluid pressure drops, it triggers a transmission fault warning message on the screen.

Which errors are shown as a result of this cause? 

Some of the error codes are 4E87, 4E86, CF07 that may be shown when the mechatronic sleeve breaks or if it is damaged. 

How to fix this BMW transmission malfunction?

The only way to fix these errors is to change the sleeves completely as a repair might be a temporary fix and the same problem may arise later.

Why does a damaged or worn-out solenoid cause a BMW transmission malfunction?

Because a solenoid is meant to keep the engine performance on point, if it is worn out the engine output is not the same as normal. That is why it caused some transmission lag and resulted in an imperfect drive.

Which errors are shown as a result of this cause? 

Some transmission errors are P1520, P1523, and P1397. The first error P1520 is related to the Camshaft position actuator. The second one is given when the Camshaft position actuator is jammed. The last one occurs when Camshaft position sensor B is malfunctioning

How to fix this BMW transmission malfunction?

Replacing these solenoids is the easiest and foolproof option as repairing them may result in a similar issue later. These solenoids are an integral part and if they are not taken care of properly, they may cause further damage to the transmission

Why does a low battery voltage cause a BMW transmission malfunction?

The BMW transmission needs a specific amount of voltage to function properly. If it is not getting the desired amount of voltage from the battery then it will go into failsafe mode.

Which errors are shown as a result of this cause? 

This cause may not give you a specific error but it has been experienced that a fault with the clutch position sensor is given when scanned by a tool.

How to fix this BMW transmission malfunction?

Charging your battery will most probably fix this error and the car will come out of the failsafe mode.

Why does a torque converter cause a BMW transmission malfunction?

The torque converter transmits the engine torque to the wheels via the transmission. If the parts of the torque converter are not engaged within themselves properly then the transmission malfunctions and the power is not delivered efficiently.

Which errors are shown as a result of this cause?

 Fault code 30 is generally shown when the torque converter is slipping excessively. 

How to fix this BMW transmission malfunction?

Repairing the faulty parts within the converter is an option to fix this issue and also in the worst case, the entire assembly can be replaced.

Why does a faulty spark plug or fuel injector cause a BMW transmission malfunction?

 The spark plugs or fuel injectors are internal parts of the engine and if they are not functioning properly then the transmission is also affected in its working. 

Which errors are shown as a result of this cause?

P1351 is the transmission error caused due to a faulty spark plug while other errors that may manifest are related to the engine.  

How to fix this BMW transmission malfunction?

The only way to fix this issue is to replace these components and scan if the errors are gone. As spark plugs and injectors are precision parts, repairing them is not suggested.

How to diagnose these common transmission problems?

To properly diagnose these problems, you need a scan tool to read these codes from the Transmission Control Unit. Firstly, If a BMW transmission is malfunctioning, it immediately informs the driver with an error message on the screen. 

Also, there is a failsafe mode that the BMW has fitted to prevent further damage to the vehicle transmission. The causes related to these malfunctioning could range from mechanical to electrical or fluid pressure inside the gearbox. 

How to prevent these malfunctions in the first place?

Regularly changing your gearbox oil and other lubricants may save you a lot of trouble and money in the future. Although many experts suggest different number miles for servicing, your car manual will give you a proper recommendation when you should change it. 

Driving style also has a huge impact on the transmission life and its usability. Anticipatory driving will result in smooth gearshifts and prevent premature damage. Also, braking has an influence on transmission as the clutch might damage if you press your accelerator and do not release the brakes. 

The most important things you remember to prevent transmission malfunctions are that drive as recommended in the manual and service your vehicle regularly to mitigate an issue that may have arisen.

FAQs: What causes BMW transmission malfunction

What causes transmission malfunction?

The common cause of transmission failure for most of the vehicles is due to not properly following the manufacturer’s maintenance guidelines for the engine and transmission and changing the fluid and filters at the proper recommended mileage and time, especially if you are using the vehicle in harsh conditions

How do I know if my BMW transmission is bad?

You know if your BMW transmission is bad if any of the below occur:

  • Usually, your Check-engine light turns on.
  • Odd noises are heard from the transmission 
  • Odd smells come off from the transmission
  • Fluid leaks can be seen from the transmission
  • Shifting problems can be felt while driving
  • Lowered acceleration efficiency can be felt when the accelerator pedal is pressed. 
  • Shaking or vibration can be felt while driving or even when idling

Conclusion

In this brief guide, we have provided you with the causes of  BMW transmission problems and what you can do to rectify these problems before they worsen.

Citation:

https://www.youcanic.com/bmw-transmission-problems#:~:text=These%20harsh%20upshifts%20and%20downshifts,likely%20is%20the%20mechatronic%20unit.

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