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Hi all. So, i've been enjoying my 64 plate i3 for nearly 2 years now without a problem... until about a month ago when i had a strange 'Drivetrain Error' pop up on the display and i could not get it into drive. After my initial panic, i got it into drive and all was good for another week or so until it happened again. Cut to last week when we had a lot of rain over night, and i find that all of a sudden i now have the opposite problem, it won't go into park. This was a bit more alarming to me as my car is left on the drive which is at an angle, and without it being left in 'P', i am relying solely on the electro mechanical handbrake to keep it from rolling, and while it is 'N' i cannot lock the car AT ALL!

My conversation with the local BMW garage was brief, as they wanted me to get it to them and leave it with them until they had diagnosed the fault, at a cost of £99 plus the actual invoice for repairing it should i go ahead. She did say that BMW assist would come and pick it up, but she could not tell me how much this would cost, only 'roughly the same as the AA', very helpful.

The 'P' mode is just a lock for the gearbox, and when it works you can hear it engage/disengage when you select drive or 'P' for example. It sounds like a bit like the handbrake but quicker. With that in mind, i took the rear inspection cover off to have a look. The actuator in question is very easily located on the side of the motor/gearbox assembly. Mine is a BEV, so very easy to get to, i cannot say how this will differ for the REx models though as i have not seen one.

So having what i figured was the correct part in my sights, i took a rubber mallet and GENTLY(!!) gave the side of the unit a couple of taps. This was in the hopes that the part used to lock the gearbox/diff/output/whatever would free off so i can at least secure the car.

Happy to say that it worked a treat! I have attached a few pictures below to hopefully help any i3 owners with this problem in the future. I have read a few posts, not just on here about BMW replacing the part for hundreds of pounds, and to be honest, IMHO, for what that part is and does i think is a total money spin. BMW have to realise this is the faulty part, just from listening to the symptoms their customers are giving them!

I have not had chance yet, but my next step will be to remove completely and identify the cause of the failure. I am guessing that because of where it is located it is picking up moisture/road crud etc and not draining properly if at all, and my hope would be it just requires greasing up to continue operating as normal. As with most things, please take where when tinkering, i've heard all those volts going through you is no joke and i obviously can't be held responsible for any damage to you or your property if you attempt any of the above.




 

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Thanks Slash for this post! It was most helpful.

My 2017 BEV had the same problem: it would not shift to Park, leaving me to key-lock my door and manually release the charging port cover.

I found your post, gave the Park actuator a whack with the BMW tow loop, and all was well for a week. Posted about it on the My BMW i3 forum: "Unable to Shift to Park..." (I'm too new here to post links).

About a week later, I got the "Drivetrain Malfunction - Contact Service" message after a stop mid-commute. Long story short, the car started normally about an hour later. The error message appeared immediately upon startup, and NOT when trying to shift to Drive, so I didn't suspect the Park actuator was at fault.

I'm curious if your Drivetrain Malfunction was similar, or only popped up after attempting to shift from Park?

In my case, BMW service replaced the Park actuator, managed to get stuck, unable to drive the car during a test drive (requiring a tow back to the dealership, according to their notes), and described replacing the Park actuator again, this time making reference to a programming method to initialize it.

Problem is, I don't know whether the Park actuator and Drivetrain Malfunction are related, or two separate issues. Service noted that for my complaint of the Drivetrain Malfunction, they addressed it through a software update! In their notes, they never mentioned "Drivetrain Malfunction" or CEL when they got stuck. All of those notes were under the Park actuator line item.

All I can do now is drive the car and see if ithe Drivetrain problem pops up again.
 

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Thanks Slash for this post! It was most helpful.

My 2017 BEV had the same problem: it would not shift to Park, leaving me to key-lock my door and manually release the charging port cover.

I found your post, gave the Park actuator a whack with the BMW tow loop, and all was well for a week. Posted about it on the My BMW i3 forum: "Unable to Shift to Park..." (I'm too new here to post links).

About a week later, I got the "Drivetrain Malfunction - Contact Service" message after a stop mid-commute. Long story short, the car started normally about an hour later. The error message appeared immediately upon startup, and NOT when trying to shift to Drive, so I didn't suspect the Park actuator was at fault.

I'm curious if your Drivetrain Malfunction was similar, or only popped up after attempting to shift from Park?

In my case, BMW service replaced the Park actuator, managed to get stuck, unable to drive the car during a test drive (requiring a tow back to the dealership, according to their notes), and described replacing the Park actuator again, this time making reference to a programming method to initialize it.

Problem is, I don't know whether the Park actuator and Drivetrain Malfunction are related, or two separate issues. Service noted that for my complaint of the Drivetrain Malfunction, they addressed it through a software update! In their notes, they never mentioned "Drivetrain Malfunction" or CEL when they got stuck. All of those notes were under the Park actuator line item.

All I can do now is drive the car and see if ithe Drivetrain problem pops up again.
Hi bud, glad to hear i managed to at least help someone a little bit. To answer some of your questions, though maybe not in order... My problems started when the car would not go into Drive, it came up on the centre screen 'drivetrain malfunction' or words to that effect, and that i should contact BMW support. I found that quickly pressing the 'Start/Stop' button a few times actually bought it back to life, but that seemed to be an isolated case and ever since then it has played up going into park instead. I get the same error message on the main screen as it did when it was jammed in drive.
I think you may have been fobbed off a little there. As far as i know there is no coding for these parts, they are literally an actuator that shoots a little piston out and locks the transmission. I do feel it would be very easy for BMW Service to quite simply take your original actuator off, lube it up and refit but still charge for a replacement as i suspect customers are quite scared of working on electric vehicles. There is a chance that a normal customer would not even notice if the thing had been changed at all.
Due to other commitments (and weather) i have been unable to remove mine in order to clean it up and apply lubrication, as i was going to post on here another step by step, however mine has not yet played up again after another tap i gave it after my first post. I do feel i am on borrowed time to be honest.
 

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As far as i know there is no coding for these parts, they are literally an actuator that shoots a little piston out and locks the transmission. I do feel it would be very easy for BMW Service to quite simply take your original actuator off, lube it up and refit but still charge for a replacement as i suspect customers are quite scared of working on electric vehicles. There is a chance that a normal customer would not even notice if the thing had been changed at all.
I've been doing quite a bit of digging, just because I'm interested in this part. I, too, assumed it was a solenoid or piston that "stabbed" a gear wheel and locked the gear from turning, especially based on how it feels when I engage Park on an incline and forget to set the parking brake, and how it rolls a little then catches on something.

So what I've figured out is that the actuator, even though it's commonly referred to as the Park Actuator, more formally is named the "Transmission Motor Actuator" or "Transfer Case Motor," part no. 27217645837.

And rather than "stab" a pawl out, it actually rotates what appears to be a gear selector shaft that fully enters the gear box. I believe it selects between Drive, Neutral, and Park by rotating this shaft. I've yet to find a cutaway diagram of our transmission to verify this.

Here's a picture of the business side of the actuator. You can see it's a splined interface so the shaft can move in and out as it is rotated:

drive-actuator.jpg

Here's a picture I found on an eBay ad showing the splined shaft that the actuator engages:

spline.jpg

And here is a video of the transfer case being assembled, where you can see the splined shaft extending out from the aktuator and though the gearbox. That might be an very tight worm drive at the other end, but I can't say for sure.


As for programming after installation, these are the notes from the technician. I misinterpreted the first time and thought the actuator was installed twice, but actually looks like just once after the problem was observed.

"AFTER PROGRAMMING AND A ROAD TEST, THE PARK LOCK FAILED AND THE CAR WAS STUCK IN PLACE. CONNECT REMOTE LAPTOP AND PERFORM A VEHICLE TEST. PERFORM TEST MODULES AND CLEAR FAULTS IN AN ATTEMPT TO MOVE THE VEHICLE. IMPOSSIBLE TO GET CAR OUT OF PARK LOCK. INSTALL DOLLIES AND TOW BACK INTO SERVICE."

"CONNECT ISID AND PERFORM A FURTHER TEST. OBTAIN DIAGCODE TO REPLACE PARK LOCK CONTROL UNIT AND EME. FILE TC CASE -- THEY SAY TO INSTALL THE PARK LOCK ACTUATOR FIRST AND THEN SEE WHAT HAPPENS. REPLACE PARK LOCK ACTUATOR AND PERFORM SERVICE FUNCTION TO INSTALL AND THEN TEACH IN THE NEW ACTUATOR."

So the good news is that the problem was observed by the BMW service department, and the actuator was replaced under warranty. I only hope this solves both of my issues ("Unable to Shift to Park" and "Drivetrain Malfunction" error messages). Because in my case, the Drivetrain Malfunction message popped up immediately; it didn't wait for me to try to shift to Drive.

If anybody finds a cutaway diagram of this gearbox, photos, or a video of the internals in use, I would love to see it!
 

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I've been playing with the actuator a little and want to retract something I wrote in my previous post.

I noticed the actuator was being activated when shifting into and out of Neutral, but only when shifting out of or into Park. Once in Neutral, if I shift to Drive (or Reverse), the actuator isn't used again. So Slash, you're correct, it's only used to engage Park (and does this mean Neutral in the i3 simply allows the electric motor to freewheel?).

I mentioned I wanted to find an exploded view diagram of the gearbox? I found a poster-sized one! It's at about the 1:00 mark in the video, behind the worker, on the factory floor!

Anyhow, I went back through the video I linked to and pulled the following screenshots.

I believe this is the input shaft with the primary pinion drive. Sandwiched between the gear wheel and the bearing is the Park Lock Ring. When one of the detents on this Park Lock Ring is engaged, the drivetrain becomes immobilized at the motor input shaft.
i3-park-lock1.jpg

This photo is showing the gearbox case before the installation of the reduction gears. The Yellow arrow points to a "Park Bar" and a Key that engages the Park Lock Ring from the above photo. The Orange arrow points to the pivot that this bar is affixed to. The Red arrow is parallel to and in line with the shaft that the Park Actuator rotates. When this shaft is rotated, is pulls the Park Bar in the direction of the Red arrow, so that the Key engages the Park Lock Ring.
i3-park-lock2.jpg

The last photo is after the reduction gears have been installed, and the circled area shows the Park Bar and Key next to the Park Lock Ring.
i3-park-lock3.jpg

So my question remains, am I damaging anything if I accidentally allow the car to "roll into park" when I forget to set the parking brake?
 
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