Strange Transmission Issue

[musa]

My 2015 X6M (47k miles) lately has started having a strange transmission issue wherein it would drop to 1st gear from D if I suddenly swerve either to the left or right at a slow speed, say 30mph. It wouldn't upshift staying on 1st and I have to re-engage D, my typical mode of driving. I realize it has shifted to 1st when the rev suddenly goes high. Not good.

Has anyone had this issue? Any ideas?

Thanks.

[F85MTuNED]

Shit that sounds weird.. I'm going to try to mimic what you said today, I usually drive in manual mode even if I'm driving like grandma or the stig (&#128514 I'll see what happens and get back to you.

[HPIA4v2]

I noticed that as well, for some reason it gets into Sequential mode from D.

Any one knows if the slow-speed assistance mode also prevent the shift-up? Aka, the car can only gets to 1-2 gear only?

I bought a 2017 CPO so I will keep an eye on it, and if I can't explain this from user manual (page 81-85), I'll take it to the dealer.

[DgjoX6M2016]

Originally Posted by HPIA4v2

I noticed that as well, for some reason it gets into Sequential mode from D.

Any one knows if the slow-speed assistance mode also prevent the shift-up? Aka, the car can only gets to 1-2 gear only?

I bought a 2017 CPO so I will keep an eye on it, and if I can't explain this from user manual (page 81-85), I'll take it to the dealer.

Is it some engine braking algorithm to slow the car down given the low speed maneuver?

[musa]

Originally Posted by DgjoX6M2016

Is it some engine braking algorithm to slow the car down given the low speed maneuver?

It does seem like an anomaly to me as I don't think it used to happen before. It does happen even when you come to a stop and then take off - it switches from D to sequential mode by itself. The fact that it overrides the driver's selection (D) and switches to sequential on it's own without driver input at all, sounds like a bug to me. My wife used to complain about it and was puzzled until it happened to me. It can be quite alarming when you drive off in D, stop or swerve at a slow speed, drive off and realize the vehicle is in sequential mode when you hear the engine revving hard.. Hopefully it's some software issue only.

[HPIA4v2]

Originally Posted by DgjoX6M2016

Is it some engine braking algorithm to slow the car down given the low speed maneuver?

IMHO, doubt it.
I really believe the issue stems from driving style, and happens when you come to complete stop, when you try to take off the gear won't shift up, THEN you realize it's in Sequential mode not in Drive mode anymore.

[musa]

Originally Posted by HPIA4v2

IMHO, doubt it.
I really believe the issue stems from driving style, and happens when you come to complete stop, when you try to take off the gear won't shift up, THEN you realize it's in Sequential mode not in Drive mode anymore.

So it's by design for the transmission program to switch from Drive mode to Sequential mode by itself? How does it make this decision, from what input? The car is always driven in Drive mode. Is it mentioned anywhere in the manual or technical bulletin of our transmission type?

Thanks.

[musa]

There's now a downloadable PDF of the owners manual.
https://www.bmwusa.com/owners-manuals.html
Here's what it says:
Flashing display on the selector lever The actually engaged transmission position can deviate from the selector lever position in
some situations. The display in the selector lever flashes. Observe the display in the instrument cluster, refer to page 80, in these cases.

When this happens I'll see if the flashing actually occurs.

[HPIA4v2]

Originally Posted by musa

There's now a downloadable PDF of the owners manual.
https://www.bmwusa.com/owners-manuals.html
Here's what it says:
Flashing display on the selector lever The actually engaged transmission position can deviate from the selector lever position in
some situations. The display in the selector lever flashes. Observe the display in the instrument cluster, refer to page 80, in these cases.

When this happens I'll see if the flashing actually occurs.

I believe it's part of slow speed assistant feature.
I think this happens to me again this morning, you can try this too:
1) D-mode, stop at traffic light flat or slight incline seems
2) let go the brake but don't touch accelerator yet (trying to be smooth), this seems to tell the DME that you want slow-speed assistant. To get out either you hit the lever to D-mode again or hit the brake to disengage the feature.

Like I said yesterday, most likely driving style, if you always drive aggressively, maybe you'll never see this.

[secretariat]

I've experienced this also. Reversing out of my driveway and then putting transmission in drive at very slow speeds it switched over to manual mode and I only knew because the engine was revving high when I gave it some gas. It happened a couple of times and I thought I accidentally put the transmission in manual mode. I didn't realize this until I read this thread. Thanks for the thread. I'll look out for this next time.

[HPIA4v2]

Next topic, try putting the transmission in park with engine running after driving

it's a trick question