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Discussion Starter #21
I think I'm being stupid, steptronic is just BMWs name for their auto box isn't it? I'll just go ahead and order a used shifter unit.
 

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Keep us informed, i doubt there’s any problems with the box at that mileage, i had one one 186k no problems i’ve currently got one on 162k no problems, that box is bulletproof unless you start chipping the motor and increase torque.
 

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i know of plenty boxes that have needed attention,,one guy got whole gearbox replaced under warranty,,var was an 06 335d e92 se,,with only 70k miles,,he sent adaptions off to zf who sent him results of the clutch condition etc,,he then took them to bmw,,he had the gearbox serviced before all this but it didnt fix the jerky gear changes etc,,adaptions reset ..went away but came back within 500-1000 miles,,so as ive said he got new gearbox,,bill was £7k but his warranty covered it..try the shifter as i said,as i k
now that can cause gear selection probs
 

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With mechanical selector lever the D/S and M+/- are simple micro switches. Disconnect wiring to those switches to rule out if the problem is on the switches or wiring. I would still double check the wiring because it's a common problem and it would be unlikely that more than one micro switch has failed at the same time.

 

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Discussion Starter #25
With mechanical selector lever the D/S and M+/- are simple micro switches. Disconnect wiring to those switches to rule out if the problem is on the switches or wiring. I would still double check the wiring because it's a common problem and it would be unlikely that more than one micro switch has failed at the same time.

That's interesting, is it just a case of disconnecting a multi plug? There are quite a few plugs under the gaiter. I've already tried it with the two plugs to the gaiter plate disconnected, the problem persisted but the paddles didn't work (that ruled out the paddles being the issue I reckon). I wonder if it will still work ok with all the connectors unplugged? The actual P/N/R/D is mechanical after all. If so, that could potentially point directly to the shifter unit if the problem disappears.
 

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If you look at the link on my previous post steptronic switch connector X1561.
Wire colours:
*brown/black
*blue/yellow
*blue/grey
*white/green

If the wires short to ground it's the same as activating the micro switches.

If the paddles are original they have a separate signal line directly to transmission control module. Of course you first have to set it to manual mode with selector lever.
 

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Discussion Starter #27
Oh, I didn't notice the link, thank you. Are you suggesting that the wire/s in question may be shorting to ground and that could be causing the problem? Can they be isolated by unplugging a connector?
 

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If you look at the link on my previous post steptronic switch connector X1561.
Wire colours:
*brown/black
*blue/yellow
*blue/grey
*white/green

If the wires short to ground it's the same as activating the micro switches.

If the paddles are original they have a separate signal line directly to transmission control module. Of course you first have to set it to manual mode with selectorTryg
If you look at the link on my previous post steptronic switch connector X1561.
Wire colours:
*brown/black
*blue/yellow
*blue/grey
*white/green

If the wires short to ground it's the same as activating the micro switches.

If the paddles are original they have a separate signal line directly to transmission control module. Of course you first have to set it to manual mode with selector lever.
you don’t have to move the lever to manual mode to activate the paddles, they are live at any time, if the lever is left in manual then the box reverts back to “D” mode after a short period of inactivity, that was my logic behind my original reply, there could still be a paddle wire shorting to earth so i suggested coding them out temporarily so the ecu in the gearbox would ignore signals from the paddles, however if the wiring in the shift lever is a known failure point then that should be the OP’s first investigation. A short from either control point could instigate the same symptoms
 

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Discussion Starter #29
I found the connector on the shift mech with the wire colours suggested above. I disconnected it which rendered the D/S mode and shifter operated gear up/gear down inoperative. The problem persisted. This would rule out an issue with those micro switches. I still haven't been able to rule out the paddle switches but I have no idea about 'coding them out' and I don't know anyone that could do that. I wonder if it could be a wiring issue between the shifter and the TCU? I'm guessing that would be extremely hard to diagnose though! It can't be the TCU itself I wouldn't have thought, as that would throw a dash light wouldn't it? There is another black connector directly under the blue one that I disconnected which I haven't disconnected but I'm presuming that this is the wiring for the dash panel to display P/R/N/D? I will try disconnecting that too tomorrow but I doubt that it will help. Is there a way to disconnect the paddle switches physically without having to have them coded out?
 

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If you follow the schematics I previously linked you can disconnect the paddles by removing connector X1880 on steering column. You could also remove connector X14271 on junction box but that would drop out so many other things that the vehicle would not work correctly.
 

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If you follow the schematics I previously linked you can disconnect the paddles by removing connector X1880 on steering column. You could also remove connector X14271 on junction box but that would drop out so many other things that the vehicle would not work correctly.
[/QUOTE
If you follow the schematics I previously linked you can disconnect the paddles by removing connector X1880 on steering column. You could also remove connector X14271 on junction box but that would drop out so many other things that the vehicle would not work correctly.
removing X1880 is a good call as this eliminates the squib ring which i feel could be a week point and does most of what coding out the paddles would do
 

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Discussion Starter #35
Thanks so much for all your help so far chaps. Isolating the paddles by removing X1880 sounds like a great call for elimating the paddles. I'm pretty sure (hopeful!) that it is the paddles now as with the shifter wires disconnected, other than if it's a problem with the wiring itself, I can't see how the shifter could be causing the issue. I tried disconnecting the other (black) connector underneath the one you suggested this morning but that immediately threw up a light/warning for transmission control on the dash and I couldn't shift the lever out of park, so that's not relevant to this issue I don't think. Clavurion, can you advise me as to how to access the X1880 connector please? Would the wheel need to be removed?
 

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Discussion Starter #36
SOLVED! After removing steering wheel airbag, look what I found on the connector...thanks so much for all your help with this, I can't believe it's actually going to cost me nothing at all to fix! The exposed core was obviously shorting on the back of the airbag.
268608
 

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I can just picture you now sitting in a leather chesterfield recliner wearing a smoking jacket with a large glass of brandy in one hand and a fat cigar in the other hand wearing a shit eating grin and muttering “ i knew i would win”
 

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Discussion Starter #38
I can just picture you now sitting in a leather chesterfield recliner wearing a smoking jacket with a large glass of brandy in one hand and a fat cigar in the other hand wearing a shit eating grin and muttering “ i knew i would win”
That is SO accurate 🤣
 

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Discussion Starter #39
It just goes to show though; you should always get second/third opinions from 'professionals'. The first was convinced an oil change and flush would solve it (~£300 if you can find someone to do it), the second wanted to strip and rebuild the gearbox (~£2000++), the third: 'it's not the gearbox mate, definitely not...it'll be the controls'. Bloody well done that third auto specialist, he was really helpful on the phone too. For reference it was 'Automatic Transmissions Preston Ltd.' Automatic Gearbox Repairs Well deserving of a mention (y)
 
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