By YOUCANIC on May 8, 2019
A common problem many BMW owners face is the automatic transmission not shifting or erratic shifting. The first sign of BMW transmission problem is the Trans. Malfunction Drive Moderately message pops up on the screen.
Symptoms of BMW transmission problems vary. Your BMW may be running fine and then all of the sudden you get a transmission fault warning plus the car goes into Safe Mode/ Limp Mode. The transmission will no longer shift or go in reverse.
Troubleshooting BMW transmission problems yourself is possible. Often times not only can you fix the problem yourself, but you can fix the problem by replacing only the defective part instead of replacing the transmission. Let's start with the most simple and basic troubleshooting steps.
If your BMW displays a transmission error message or is stuck in gear, the first thing you should do is find a safe location, turn off the engine and restart the car.
Wait at least one minutes and start the car. This may reset the transmission and the transmission malfunction message may turn off, which should allow you to get back on the road.
If your BMW is back to shifting normally don't assume there is no problem. There is a high chance that you will experience the same transmission problem again.
While the problem may not seem major, if you ignore it, it can eventually get worse to the point that your BMW will no longer shift gears.
If you have noticed that your BMW has erratic shifts or is not responding properly the problem may be fixed by following a few simple procedures that will allow you to reset BMW adaptive settings. This procedure is very simple, requires no tools and only needs a couple of minutes.
BMW Transmission Reset Procedure
This will reset your transmission shifting to original factory settings. In other words, the BMW will erase the transmission shift points. For the next few driving cycles, your BMW will be monitoring your driving patterns; it is NOT recommended to drive aggressively.
Hopefully, this fixed your problem but if the symptoms will return again continue to the next step.
The next step is to read the fault codes. You will need a BMW specific OBD2 scanner that can retrieve fault codes from BMW modules.
Typically you will be able to get a good scanner in the $100-$150 range. Generic OBD2 scanners won't help you with this task.
If you use a generic OBD2 scanner you will get generic fault codes such as P0720 or P0732 which don't provide enough details on what could be the cause of the problem.
What we used: Foxwell NT510 for BMW
Alternative scanners: Top 10 Scanners for BMW
You should at a minimum read fault codes from the Transmission Module (EGS Unit), but a full system scan is recommended. Sometimes you may find there is DSC or ABS fault code. It is possible that a fault code in these systems can put your BMW automatic transmission into Fail Safe mode even if there is nothing wrong with the transmission.
Erase all the codes. This will erase any stored codes and current codes. If your BMW transmission is working properly, great. If your BMW is still in Failsafe mode read the codes again.
If transmission malfunction drive moderately error message pops up on your BMW, one thing that you should always check is the automatic transmission fluid level. If the trans level is low, even slightly, your BMW will go in limp mode to protect the transmission.
It is typical for a small amount of oil to leak especially in high mileage BMW. Add the missing transmission fluid, but do not overfill the transmission above the recommended level as this can cause shifting problems as well.
Typical signs that the transmission fluid level is low, is that your BMW displays the Transmission Failsafe Prog." Warning if you try to accelerate by flooring the gas pedal or when accelerating as you are making a turn.
This happens because more transmission fluid is required during acceleration or the fluids gets pushed to one side of the trans oil pan when making a turn. Which means there is no transmission fluid for the oil pump which causes the transmission to go into FailSafe or Limp mode.
How to check BMW transmission oil
What you will need:
Only used the recommended transmission fluid for your BMW.
If you experiencing random shifting issues, consider changing the automatic transmission fluid and filter. There is a lot of discussions and often disagreement whether you should or should not change the automatic fluid in a BMW especially on a transmission that is sealed for life.
In our experience, fresh fluid and transmission fluid will only help to extend the life of the transmission. The only times that things get worse, is when there is an already existing issue with the transmission.
A BMW automatic transmission holds about 9.5 qt of ATF fluid. That is full system capacity, which includes all the oil in the transmission, oil pan, and torque converter. If you are not going to flush the whole system but only drain the oil pan you need about 4.5 qt of oil.
Check for an oil leak at the electrical connector. The mechatronic sleeve is located on the passenger's side of the transmission near the end of the automatic transmission. This is where the wire harness from the Transmission Control Unit (TCU) connects the transmission.
This is usually near the back of the transmission. If you unplug the wire harness, you may notice an oil leak at this plug. If there is any oil, not only it means you are losing oil, but the communication between the ECU and the mechatronic valve body is interrupted.
To replace or check for leaks you will need to get your BMW up on ramps. Remove the splash shield from under the transmission and unplug the wire harness.
What you will need: BMW Mechatronic Sleeve ( Part #: 0501 216 272 01)
Another reason why a BMW may display “Transmission Fault” warning message on the iDrive screen is due to a cracked adapter (trans seal grommet) for the mechatronic valve body.
Under normal condition the grommet allows the fluid to flow from the transmission to the mechatronic valve body without any fluid loss.
This allows transmission fluid to make it to the mechatronic without any pressure loss which in turn allows normal gear shifting.
The grommet or the plastic adapter can crack over time, which allows the fluid to leak at this port. When this happens the fluid pressure at the mechatronic valve body is reduced.
Because the fluid pressure is reduced the solenoids in the valve body cannot open and close properly which triggers the transmission fault or erratic shifting.
This part is easy to replace and comes in plastic or aluminum.
The OEM part sold at BMW is usually plastic, but upgraded aluminum adapters can be purchased online and last longer than the plastic version.
This problem is common on these BMW transmissions: 6HP26, 6HP28, and 6HP32. An improved Aluminum Part Number SFC-MA-001 is available.
Another indicator that this part is broken is that you will get the “transmission Fault” popup typically when you move the shifter from drive to reverse. You usually back up a few feet and put the transmission back in drive.
What you will need:
BMW Mechatronic adapter (Part #: 0501 215 783 01)
List of cars most affected by this problem:
If you checked everything above but are still having problems with your BMW transmission the cause most likely is the mechatronic unit. If you are looking to save money, you can consider replacing only the solenoids in the mechatronics unit/valve body.
If you decide to replace the solenoids yourself, remember to change the foam strip that goes between the solenoid terminals and connectors.
If you want a unit that has already been remanufactured and tested, you can buy a remanufactured BMW Mechatronic unit online. If you have some basic DIY skills, you can replace the mechatronic unit on a BMW.
Keep in mind that the unit often needs to be codded to match your BMW VIN. Before you purchase a replacement mechatronic unit, check with the seller or BMW dealer if programming or coding is required.
It is possible to replace BMW mechatronic yourself.
If you would rather let a mechanic do the work, this repair can cost anywhere from $1500 to $3500. If you decide to have the dealer replace the mechatronic on your BMW, it will usually cost anywhere between $2100 and $3500.
It is recommended to reset the transmission module after the Mechatronic replacement. Drive the vehicle around for about 15-20 minutes making sure transmission cycles through all the gears several times to recalibrate the shift points.
BMW often comes up with software updates for the automatic transmission. These updates change the shift points which improves the shifting.
In some cases, it has been reported to fix erratic shifting problems or SAFE MODE issues. You will need to call your BMW dealer and ask them if there is a software update for the transmission for your particular car. You will need to provide the dealer with the VIN number of your BMW.
We have seen cases where the BMW transmission will get stuck in second or third gear and will not come out of failsafe mode even if you restart the car. In one case this problem was caused by a dead battery that stored hard codes.
Even though the BMW battery was replaced the car remained in Failsafe mode. Typically a BMW will go into failsafe mode if the voltage is under 9 volt.
If a hard code is stored in the EGS module you will need a BMW Specific Scanner to clear the fault codes from the EGS module. Low battery voltage can also cause the transmission to not go into Drive or Reverse.
Often the transmission issue may be with due to a problem with the first gear only. To verify that the problem is with the first gear, set your BMW transmission in Winter mode, which forces the transmission to start in second gear.
If your BMW shifts normally when in winter mode that means there is an issue with the first gear. Keep the transmission in winter mode, until you get your BMW transmission repaired.
If your BMW is stuck in park and the shifter won’t come out the problem could also be the brake light switch or park solenoid.
BMW that are equipped with twin turbo may experience shuddering symptoms, especially during a long trip. To verify that this is the issue, it is recommended that you stop your car and let it cool down.
If transmission shuddering symptoms go away when the engine cools down then it is possible that the problem is caused by the twin turbos. Check engine light may also come on. Symptoms often happened between 50-70 mph.
Another reason why you may experience transmission shudder is due to issues with the torque converter. This is often due to the fact that the torque converter lock-up is wearing out and not locking the torque converters.
BMW transmission shudder may also be caused due to spark plug or fuel injector problems. If the check engine light is on, make sure to scan the codes from the ECU so that you can get a better idea of why the transmission shuddering is happening.
This is a list of common BMW transmission messages. These messages vary between models, but they all point to problems with BMW transmission.
This is a list of common BMW transmission fault codes.
This list does not include all BMW EGS fault codes. A BMW scanner is required to read and clear these BMW codes.