BMW 335i N54 DCT Transmission failure!

Joachim335

New Member
Feb 23, 2023
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Hello! I have a 2009 Bmw e92 335I N54 with the DCT (GS7D36SG) transmission.

- MMP 1k Turbskies
- MMP exhaust manifold
- MMP inlets
- 7,5" Intercooler
- AFE cold air intake
- Turbosmart Chargepipe and BOV
- Catchcan
- BM upgraded PCV
- Precision Raceworks coils
- Downpipes
- MHD Stage 2
- XHP Stage 3

All this started almost 2 years ago!.. haven't had time to watch over the car before now.. And i have figured out that my problem with my exact codes isn't much information to find. So im making this long thread to hopefully help someone else out someday!..

All started with a little pull when i came out of a roundabout and the dash lighted up like a Christmas three! All yellow signs.
Aaand i drove like 200m, in 4th gear ( i think i remember right)😅.. until i had to brake down to a complete stop, because of traffic. Since then the transmission has been stuck in 2nd gear!
Whenever i put it in drive (D) i feel it goes into gear.. but i have to give some throttle to make the car move (like when you dump the clutch in a manual car) until i have enough speed to drive normally. Transmission is stuck in 2nd gear when put into Drive (D)
Reverse (R) feels same as Drive (D), i can feel it goes into reverse (R) but has to give it some throttle to make the car move.
To get the car in park (P) when standstill, sometimes the car has to be moved forward or backwards to go in park!..

The car cranks up everytime but the engine is in some kind of (Limp Mode) and the throttle won't react as normal.

The codes in MHD:

2E7F
CD87
CD9D
CD9E
CDB0
CDB4
CDB8

The codes in TCU:

CD9D
CD9E
CDB0

The codes i have in my CIC:

DSC Failure! Drive Moderately
DBC Failure! Drive Moderately
FTM System Error!
Start Assistance inactive!

The codes in MHD and XHP is gone when i start up the car after i have deleted them (With whatever Scantool i use) except from the ones in the CIC.. they are still there when restart of the car.
I delete faultcodes with MHD, CARLY and a OBD car scanner.

I have Checked/Changed:
- Checked/Updated/removed/reinstalled MHD and XHP
- Checked and cleaned the Steering wheel angle sensor.
- Checked the mosfets in the DME (MSD81)
- Checked all the wires and connectors in the DME compartment
- Voltage (good 13-14 volts)
- Battery
- Alternator Regulator
- Changed the Abs sensors
(Wheel Speed Sensors)
- Tried with original coils
- Yawrate sensors
- IBS (Used)
- gave the transmission a complete maintence service with Oil and 2 filters.(watched youtube, so it should have been done right)
- Checked internally in the transmission (it was enough oil when i opened the cap, no leaks or dirty oil.

I have pretty much landed on 3 things:
- Wheel speed sensor ring(s).. (All 4 sensors are changed)
- Transmission Harness or connector: between Transmission and DME
- DCT internal.

Hope someone can help me out here! All answers appreciated! THANKS!! 😊👍

Screenshot_20220123-222126_Gallery.jpg
 

Calamari_

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Jan 29, 2023
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Ive had this happen to me a few times, you either have a short or a entirely split PT can wire, Id look at the ones going to the transmission in the DME box first. Its because the trans doesnt know whats going on so the DSC isnt reporting torque values ect.
 

Joachim335

New Member
Feb 23, 2023
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Ive had this happen to me a few times, you either have a short or a entirely split PT can wire, Id look at the ones going to the transmission in the DME box first. Its because the trans doesnt know whats going on so the DSC isnt reporting torque values ect.
Thank you so much for your answer! i have been looking inside the dme box but i cant find anything wrong.. checked all the wires and connectors and pulled slightly in the wires going into the connectors and everything seemed to be tight and good😮💨.. i could double check tho..
Heard someone mentioned the connector down on the transmission? Could it be something down there maybe?..
 

Calamari_

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Jan 29, 2023
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Thank you so much for your answer! i have been looking inside the dme box but i cant find anything wrong.. checked all the wires and connectors and pulled slightly in the wires going into the connectors and everything seemed to be tight and good😮💨.. i could double check tho..
Heard someone mentioned the connector down on the transmission? Could it be something down there maybe?..
If youd like DM me and i can send you my number or facebook so we can really dig into it, im all about helping others since i ran into alot of these issues and only one person truly helped me, But ill give a decent explanation here aswell.

So the the main code we are looking at is the PT CAN 1 and PT CAN 2 communication fault code, all the transmission/engine data missing is due to the 2E7F code as PT Can is what allows modules to communicate together.
Theres around 5-7 modules that are tied onto this busnetwork, dont quote me on that, its around there just not really trying to math right now.
Alot of these modules we wont be worrying about either way.
Im assuming when you go to drive its a constant thing, it doesnt come and go. You get in, car starts fine but needs effort to start driving and as you get moving your RPM's get sporatic and jump asif the transmission is slipping (Which it technically is) correct?

Heres some initial spots to check before having to disconnect the entire transmission harness, this way we can run through the more common failure points

Also, just to make sure, this is a DCT swapped car correct? Did you make the wiring harness or take it off a donor car? If its a swap then im assuming youll have some idea of the locations im telling you.

So to start, open your DME box and look for a twisted set of Red and Blue/Red wires, youll see 2-3 sets of two twisted wires going around the DME box, It first comes up through the left side of the DME box (as if your looking at your car head on), i usually call this the chassis side harness as it comes from the JBE, So wire comes up from the chassis side harness (twisted PT CAn wires) and they go to two different spots, it comes up and goes to the black connector on the back side of the box, this is the start of the transmission harness, youll actually see there are two sets of red and blue twisted wires right next to each other on this connector as the PT wires loop back after going down and through the transmission, which then goes to the dme and all the wires are combined with a crimp that then go back into the chassis side harness and over to the DSC side of the car through the dash. The easiest way to really test if its a short or full on wiring issue is if you have a multimeter that allows you to check continuity id suggest using this as i cant remember that proper ohms of that PT can wires when they line is working properly, (theres three resistors on the PT line, the DSC, EKP and the DME i believe, which are all 120 ohm resistors, if everything is working properly and wires arent shorted it should be at 120 i believe, i could be wrong, when its bad youll get double that if one of the main modules/resistors arent getting the correct resistance. But testing via continuity is pretty easy, just take the black connector in the DME box, pop the side clip that exposes the pins in the connector, its going to be the 4 pins on the left side if your looking at the connector on the smaller pin side. Put your multimeter to each pin, specifically the two pins that are right next to each other since theres two sets, (Red and blue not red and red etc). Same method when testing with just ohms i just cant remember the correct ohm output. Start there and DM me and we can update the post as time goes on so someone else who is running into this has some insight on what might be going wrong as i personally havent found much on this topic.
 
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Calamari_

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Jan 29, 2023
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Having a similar issue but I only get these same codes after I flash mhd someone please help usa
More than willing to help, continued helping the other guy via PM's, was going to post updates here. Whats your exact code? Is it a PT can 1 pt can 2 communication fault code?
 

Calamari_

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Jan 29, 2023
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Yes 2e7f code accompanied by cd99 which is caused by the 2e7f
What year is your car? i noticed the PT can 1 - pt can 2 code was due to one of two things, are you having any communication problems with other modules? have you programmed the car yet? Just curious as this will help me help you, Also, if you are having communication issues with something, connect inpa to your car, go to e90, function job, UIF (f3), this will show the list of modules currently communicating with the car, a few modules to look for are, EGS, DSC, GWS,
 

Dipp

Lurker
Oct 11, 2020
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Brooklyn ny
What year is your car? i noticed the PT can 1 - pt can 2 code was due to one of two things, are you having any communication problems with other modules? have you programmed the car yet? Just curious as this will help me help you, Also, if you are having communication issues with something, connect inpa to your car, go to e90, function job, UIF (f3), this will show the list of modules currently communicating with the car, a few modules to look for are, EGS, DSC, GWS,
All coms are good code only popped up when I installed mhd. Before the install of mhd code are non existent. Fixed it by switching to a 335is dme,cas ,and key also flashed mhd with the newer mhd dongle. Not sure what did it but it works. Lol
 

Dipp

Lurker
Oct 11, 2020
15
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Brooklyn ny
Has anyone swapped a dct trans into an earlier 07 335i which has the 8 pin transmission connectors in the dme box ?
 

Calamari_

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Jan 29, 2023
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Has anyone swapped a dct trans into an earlier 07 335i which has the 8 pin transmission connectors in the dme box ?
The 8 pin as in the black, marron, blue and white connectors? I have those on mine i believe
 
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jeca19955

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Sep 4, 2023
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Hi guy, did u find the problem ? I have also Problem with dkg module(gearbox) no communication between dme and dkg
 

jeca19955

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Sep 4, 2023
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More than willing to help, continued helping the other guy via PM's, was going to post updates here. Whats your exact code? Is it a PT can 1 pt can 2 communication fault code?
Hi , seems like i have problems in say direction , could u give me some tips?