Intermittent problem with transmission not going to gear

MilkBags

New Member
Feb 28, 2018
9
Montreal, Canada
I have a peculiar issue with my car not going into gear when starting it up, or just turning the ignition on actually. It will display the car in neutral/may roll symbol, then the yellow gear cog and the P on the shifter won't light up. It is intermittent though, it may work once and then won't for several other cycles (by cycle I mean, putting the key in, turning ignition on, checking if it works or not, turning the ignition off, removing the key and waiting for the car to go to sleep) and then sometimes it will work for several cycles.

I have my friend who runs a BMW indie shop working on this and he's leaning towards the DKG being the issue. As some of you may know, that thing costs a fortune so we're trying to eliminate all other possibilities first.

We eliminated the obvious and some less obvious things: battery is good (it's new actually), alternator too, checked the wiring, checked that the GWS is not water damaged etc. We scanned the car with ISTA and it says the DKG is "partially communicating" on the LIN bus so we were thinking it may be some issue with the DKG and the GWS. We tried unplugging the GWS but the issue still happens.

The codes we get:

Engine / Motor:
003BDF - PT-CAN, message (request torque DKG, 0xB8): missing
003BD4 - PT-CAN, message (transmission data 4, 0x10A): missing
003BE1 - PT-CAN, message (transmission data 0xBA): missing
003BD8 - PT-CAN, message (transmission data 2, 0x1A2): missing
003BDB - PT-CAN, message (transmission data 3 0x3B1): missing
003BD9 - PT-CAN, message (status DKG, 0x37D): missing
00CD8F - PT-CAN, message (display transmission data

DSC:
00D357 - CAN message / lumbar Error: message LWS1 (ID 0x1F5) missing (RCV) (DSC-ECU received). / CAN fault: Embassy DELAY ANF ACC (ID 0x0AD, (ST DCRN BRP TAR ACC)) is missing! / CAN BUS CAN open F / PT-CAN transmission 1 - Transmission data message 186 missing / PT-CAN: Embassy DELAY ANF ACC (ID 0x0AD) not received (received by DSC SG). [Channel: ACC]

KOMBI:
00A3AA - CAN ID 1D2 ERROR failure message transmission data / CAN ID 1D2 ERROR message transmission data / CAN ID 1D2 ERROR message Gear data

CAS:
00A0B1 - SG input P N / SG input P N A0B1

@aus335iguy I've seen the thread you posted the pictures in and you mentioned intermittent issues as well, are they similar to what I am experiencing?

Anyone has ever seen something similar on another car? Anything else we should try?
Thank you!
 
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aus335iguy

Lieutenant
Nov 18, 2017
916
Let me start by saying im not an expert. Im just an enthusiast with a penchant for messing with things i have no place messing with :)

What you describe does sound familiar but youd have to check the other thread out to see if its exactly the same. I believe youre talking about the thread on e90 post ? In that case a replacement of the mechatronics unit fixed it. I dont believe that guy tried an alternate GWS unit(which is much cheaper to try)

Reflashing of the device was also not attempted though and these were the fixes that I recommended to the person at the time. BMW standard tools will do the flashing, you need to follow the instructions on how to flash your DCT to do it. It is risky and you could further damage your car. Either way though if these dont work itll take a replacement mech unit or in my opinion the easier route, the whole gearbox. New would cost you the gross national debt of a large country, used DCTs are getting cheaper though.
 
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MilkBags

New Member
Feb 28, 2018
9
Montreal, Canada
Hah, no worries. I'll take any information I can get.

No, I was talking about this thread but I did find the thread you're talking about on e90 later in the day while doing some more research. I read most of it (on my mobile, so I'll go back to it from my laptop) and yeah it's too bad that person "gave up" and just went with the new unit from the dealer, but I can understand his frustration and just wanting a working car back. Personally, I don't wanna spend 5 digits on this (just a new mech unit will be around $8000 CAD with taxes) so we're trying to find alternatives.

My buddy flashed it with Autologic, I'd assume it's similar to what the BMW standard tools do, but we could always do it again with the BMW tools to be sure. We don't think it's the GWS as the issue happen even when it's completely disconnected.

Yeah, we've already looked at prices for a used DCT around here and I could get one for $1500-2000 CAD and even found a used mech unit for $500 CAD, but the problem is we'll need to code it to the car which as far as we know you can't do with the BMW tools unless it's a new unit. We did find someone in California who say they're able to code it if you send them the mech, your CAS and a key (the mech needs the rolling code that's in the CAS/DME), but we're still waiting to hear back.

We even did some quick napkin map to see if swapping in a used manual tranny with everything you need, diff, linkage and even an upgraded clutch and flywheel and it still comes out cheaper than a new mech, that's how expensive it is lol. I'd prefer to keep the DCT though as I've been gathering parts for the M3 DCT swap like @dyezak did. Got the driveshaft, cluster, GWS, and shifter already.
 
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juld0zer

New Member
Feb 24, 2018
5
I've installed two donor DSC components (first was a controller and second was controller with the pump) successfully using BMW's own software (ISTA/D for the calibration, resets and fault code clearing, and ISTA/P for the programming and coding). It just recognises it as an uncoded control unit. Unless the mechatronics is deemed an item of greater significance, it may be worth a shot if you can negotiate a path of refunding the unusable mechatronics if the programming fails.

I have not cross checked ETK but I would strongly advise cross checking part numbers before going ahead. The gearbox will have to be electronically connected during the programming, and a high current power supply connected. Do not attempt programming it without the power supply as it takes around 45mins to an hour.

I have also flashed the DCT (mechatronics not swapped) using a different daten. It is unchartered territory and quite a hair raising experience given the stakes at risk. The procedure is an adaptation of the N55 DME downgrade flash. I don't encourage this method because it is very risky - i would rather kill a DME purely because it is much easier to access to replace.
 

MilkBags

New Member
Feb 28, 2018
9
Montreal, Canada
@juld0zer Coding the mech unit wouldn't be a problem, the problem would be that the rolling code (ISN) for anti-theft wouldn't match the rest of the car so it wouldn't let the car start and/or get into gear.

For the DCT flash, are you talking about the M3 GTS flash? I think I've seen you post in some of the threads related to that here. I actually want do this at some point in the future. :D
 

aus335iguy

Lieutenant
Nov 18, 2017
916
@juld0zer Coding the mech unit wouldn't be a problem, the problem would be that the rolling code (ISN) for anti-theft wouldn't match the rest of the car so it wouldn't let the car start and/or get into gear.
I dont think its as big an issue as it seems. The auto guys manage to do swaps and people swap to manuals and even boxes that dont even belong in BMWs. There must be ways no ?
 

MilkBags

New Member
Feb 28, 2018
9
Montreal, Canada
I dont think its as big an issue as it seems. The auto guys manage to do swaps and people swap to manuals and even boxes that dont even belong in BMWs. There must be ways no ?
Yeah, but no one seemed to mention what workaround they used.

Can faulty wiring harnesses (12517581112 or 28607842853) cause this kind of problems?
Absolutely. My friend checked the wiring to that plug and it was fine though. Apparently it's common for oil to get into the plug if your gasket is leaking but from the outside it seemed dry. To properly check it you need to drop the tranny which my friend is probably gonna do today.
 

mad1stgen

Lurker
Sep 19, 2017
12
I always thought DCT was part of ISN check, but it would appear it isn't from recent posts.
Anyone who retrofitted a DCT in place of auto or 6mt should be having the same issues then ?
 
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