6AT jumping out of gear strange codes

Blackarrow335i

Specialist
Nov 5, 2016
86
59
0
Simpsonville, South Carolina
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BMW 2009 e92 335i N54 ST
Edit: just took the car for a spin nothing crazy no wot or anything, logged my voltage on KL15 with protool and noticed that I get Voltage fluctuations! While driving/idling it goes as low as 12.4V
So Voltage fluctuation from 12.4-13.8V car

Edit: checked voltage with multimeter (battery, under the hood terminals and alternator) all 14.4v at idle with all accessories on. Car off 12.6V

Edit: while checking the voltage at idle I gave it a little throttle (tiny bit) kept it there but rpms kept climbing to almost 5k (video is attached)

Edit: still have the feeling this might be Voltage related, not 100% sure if that’s true or not but that’s my gut feeling. I Unplugged the IBS sensor at the battery completely so it’s literally just a ground cable at this point,
Still not seeing 14V not with MHD and not in the hidden Menu 13.8-13.2 is where I’m at no matter what!
Came home from work pulled codes and got bunch of them picture is attached I wasn’t able to regenerate those codes also first time all those codes popped up since all this is going


Hello everyone, can someone help me out please?
2009 e92 N54 AT 6266 ST stock at with xhp s3
Since quite a while I have a strange issues going on.
A few month back (April or May) I installed my ST everything worked out well car ran fine on 14psi WG pressure then we started tuning
Got to about 19 psi and suddenly my transmission won’t stay in Gear/Mode example: DTC off M3 then wot and as soon load increases it will jump into either D6/S6 or D5/S5 usually nothing else happens also don’t get any codes (not in MHD and also no codes with xhp) and can just shift as nothing happened and keep on driving. But sometimes (same example as above) and transmission goes into safe/limp mode and stuck in 3rd til I turn the car off and on and everything works fine! That’s when I get codes please see picture!
I thought well time to rebuild my transmission so I did with PD clutches and bushings and a rebuild valve body I mean rebuild not just a sonnax zip kit!!! Installed the transmission did the relearn process etc. everything seemed to be fine and we kept on going now we are at 21psi but the one day same shit happens again car won’t stay in gear/mode! Then next day car drives and pulls fine for weeks and suddenly same shit again! It’s coming and going!
What I did so far! Changed our entire engine and transmission harness but not injector harness, replaced ground strap,replaced battery checked mechatronic sleeve connector to make sure it’s not leaking and plug sits flush 3mm from housing to plug as the ZF manual states, and as I said earlier it’s pretty much a brand new transmission! Sometimes it works fine then this shit happens and the next minute it pulls fine again! Please help I’m lost at this point!

TIA

Link to video if what It looks like


 

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Last edited:

Rob09msport

Major
Oct 28, 2017
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Monroe CT
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09 335i msport le mans 18 x5
So I should ditch the 160 ?
What confuses me is even stock driving softly in normal weather stays 17x for me without cooler. I just ordered a cooler with 160 degree thermostat but maybe I'll get a 185 improved racing and use the 160 on my oil cooler. Oil should be fine running 180 cause will usually be hotter by few degrees in engine and also will be under vacuum at different times so that lowers boiling temp.
 

iminhell1

Sergeant
Jun 17, 2018
419
207
0
So I should ditch the 160 ?

Yes.
No doubt in my mind.


With the factory setup, normal temp was about equal to coolant, around the 190 range. Beating on the car it'd climb.
I damaged the cooler and just looped it.Took longer to warm, and once warm a lot longer to cool = less fun time beating car.
Put the cooler in, never warmed past 155, even 20 min lapping sessions.
Trans took a shit.
Added thermo and have yet to test. ... doing JY trans and single turbo swap
 

iminhell1

Sergeant
Jun 17, 2018
419
207
0
And the one thing that's remained constant for me and my trans sagas is that any time I get close to a 1.6x 60' the trans acts up. I've done a few mid/low 1.7's and the next go round I'm always like awesome that's what I have to do again. Then the trans acts up.
Just from thinking back I'm prettty sure all my 1.7''s have been with trans temps over 200 and probably over 220 even.
 

Blackarrow335i

Specialist
Nov 5, 2016
86
59
0
Simpsonville, South Carolina
Ride
BMW 2009 e92 335i N54 ST
How did you repair it?
Solder can break, if it's not a clear heat shrink you have to cut it off to see what's going on.

I had real similar situation as you. I thought I solved it 3 times and every time it'd come back.
I first though it was tune related, tried different OTS tunes, same result, though took varying times for problem to arise.
Replaced battery. Was fine for a while. Mind you I'm adjusting tunes all the time here.
Comes back. Found an error in part of the base tune I was using. Corrected it and car felt much better.
I added a trans cooler because last track outing I let it get warm enough to the slip point, about 250*F. It went into failsafe.
Since I added the cooler it just hasn't worked the same.


From what ISTA says, trans temps have to get to and above, don't quote me because I don't have it right in front of me, 180*F for learning to take place. I haven't got that high since I put the cooler in. And TBH I think that's what killed my trans ... no word on what or how yet.


So I'm kinda thinking that while you went through the steps for the trans relearn, they weren't done to the letter. As far as I can guess that trans temp is a very big deal and needs to be spot on.

I also think that there is an issue with the user adjustments through xhp and that a conflict lies between that software and mhd.




And what my trans did the first time there was a problem was default to 3rd gear, I was doing 120. How the F does and auto moneyshift?
Thanks for the detailed info I’m going to change the entire shifter to make sure it’s not the unit itself nor the wires! I will double check those wires on the replacement shifter first!