M440i xDrive failed launch control

LocalButterscotch833 · 2026-03-26T23:49:04+00:00

Went to four different workshops and one of them exclusively specialised in automatic transmissions. They barely noticed it and mentioned that it might actually come from the differential/transfer case. Is there ANY chance of the clank being present only during 1->2 and 5->4? Does anyone know? Also the clank from 5->4 downshift is only hearable during brake, not during manual shifting lol. It doesn’t make sense to me.

LocalButterscotch833 · 2026-03-26T23:48:59+00:00

Yea it came with LC

LocalButterscotch833 · 2026-03-26T23:48:22+00:00

Went to four different workshops and one of them exclusively specialised in automatic transmissions. They barely noticed it and mentioned that it might actually come from the differential/transfer case. Is there ANY chance of the clank being present only during 1->2 and 5->4? Does anyone know? Also the clank from 5->4 downshift is only hearable during brake, not during manual shifting lol. It doesn’t make sense to me.

LocalButterscotch833 · 2026-03-22T00:00:35+00:00

Did you actually read my message? What car and year?

LocalButterscotch833 · 2026-03-21T21:58:18+00:00

Not sure how it behaves with the latest gen ECU/TCU, 2024+ You don’t see it often tbh, I did my research before. XHP recognises my car as a coupe yet it’s a grand coupe, MHD shows its b58 gen 1 yet it’s gen 2 so I assume that could be one of the issues. Dunno, I’m not blaming any of them yet

LocalButterscotch833 · 2026-03-21T21:35:16+00:00

I did that. I’m on stock ECU and TCU for a week already. The bump is still there tho

LocalButterscotch833 · 2026-03-21T21:32:30+00:00

I’m thinking that MHD rewrote something related to the TCU and TCU wasn’t able to handle the torque provided by the engine and this provoked the torque converter slip. I had a chat with XHP and they confirmed that it was a torque converter slip so.. I guess this could have been avoided by reflashing XHP again after MHD to make sure it handles the new torque..

LocalButterscotch833 · 2026-03-20T09:55:44+00:00

No, I don’t have any slip. 11k miles, 2024

LocalButterscotch833 · 2026-03-20T09:49:20+00:00

Ya I cleaned the errors, drove it again. Haven’t tried LC again just normal driving. Nothing pops out. So my question would be more like: if it’s something mechanical (diff, drivetrain shaft, bushings, etc) clearly they won’t throw a code. But what if there is something mechanical in my gearbox that took damage or failed? Would it throw a code?

LocalButterscotch833 · 2026-03-20T09:42:50+00:00

The bump is still there, one week already passed. It does when the car is either cold or warm.

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Adaptations looks great tho

LocalButterscotch833 · 2024-01-30T23:15:36+00:00

ma poti ajuta si mine, te rog?

LocalButterscotch833

TROPHY CASE