BMW 1 Series Coupe Forum / 1 Series Convertible Forum (1M / tii / 135i / 128i / Coupe / Cabrio / Hatchback) (BMW E82 E88 128i 130i 135i) - View Single Post - N55 with DCT RPMs fluctiation with AC On Finally Resolved!

Ganque · 06-05-2016, 12:22 PM

*** N55 w/DCT issues resolved***

Hey everyone! I've been having issues with my DCT when the AC was on for a while now... Months and months of research and I've finally found the solution!

I've been having an issue with my car for a few months now, actually it started after installing my BMS Intake for the N55 engine. The car started to act weird whenever the AC is on and coming to a stop. I've been doing research for months trying to address this, and thinking that could be anything else but the BMS Intake. I checked on several forums in so many languages, most of them said that the symptoms matched with a Service Bulletin (SIB 12 15 14), and 99% of the times I posted my issue people replied back saying that this is a software issue and I should go to the dealer to get my DME updated.... I did it twice, and got charged for getting my DME updated twice because I'm out of warranty... So I've spend around $400 USD just trying to get this resolved by the dealership, of course no luck and still having the problem.

Let me try to explain you the details on what was my issue:

Symptoms:
- Engine Stuttering at low RPMs when coming to a stop only with AC on.
- Jerkiness Stalling with A/C
- Car jumps forward when coming to a stop... it kinda feels like when doing a "heel-toe" downshift from 2nd gear to 1st gear including a knock noise from the engine fighting to keep it running on very low RPMs.
- The car started to have these issues since I installed the intake, I did not touch the MAF sensor or anything else.

Current mods on my car:
- JB4 with ISO mod and JB4 connect kit
- BMS Intake
- Helix FMIC
- Megan Racing Downpipe
- Mid resonator deleted
- COBB Chargepipe

Actions already taken to attempt to fix the issue:
- Took the car to the dealer for a software update (Mentioned the SIB 12 15 14) twice...... Didn't fix it
- Did a DCT adaptations reset via Tool32 on a K+DCAN cable.... Didn't fix it
- Did a Throttle Adaptations reset (regular pedal procedure)...... Didn't fix it
- Updated my JB4 firmware to the latest version and switched to Map 5.... Didn't fix it
- Regular oil change on the N55 engine.... Didn't fix it
- Scanned the car for old codes... No codes saved
- Checked for Boost or Vaccum leaks... No leaks found

So after 5 months of just trying to live with this issue on hot summer days here in Mexico, I was even thinking on getting rid of the car... Someone in one of the million posts I made asking for a solution told me this:
"It's your bms intake go back to stock intake problem solved"

After all the issues that I've been going through I decided to switch back to the OEM Intake.... and that was it!
No more fluctuation and jumps at low RPMS, holly cow. It's funny how I spent months on doing research, looking everywhere except for the intake.

Now, the thing is, isn't this something that BMS should be aware of and warn the customers when ordering their products?
Even if it's only under specific engine, transmission and mods, it still needs to be addressed, and I'd like to have a refund on my BMS Intake... or any other compensation, I now know that I can't have an intake on my car which sucks so bad.

So in theory, the BMS Intake was getting more air during low RPMs which made the engine run lean at a certain point during the downshift from 2nd to 1st gear, so when the DCT tries to do the RPM matching action the RPMs are higher than expected.

So after all this bible... here are the steps to perform when trying to detect and fix the issue:
1) Make sure the issue happens with a DCT (or DKG) transmission with the AC on.
2) If so, please check your current software version on your DME, if you don't have a K+DCAN cable or access to ISTA/D please take your vehicle to the dealership and ask for a software update. If you are out of warranty they will charge you somewhere ~$100-$200 USD to update it depending on the amount of modules your car requires an update.
3) If this doesn't fix your issue check your engine, if you have an intake, put back in the stock one and take it for a test drive.
4) If the issue is still happening, do a boost leak and vaccum leak test.
5) Depending on your milleage make sure to do service on your DCT every 30k miles.
6) Check for Spark plugs and coils.
7) Perform a LPFP and HPFP test.

Hope this information helps anyone who might be having the same issue.
Cheers!

************ UPDATE FOR OPTIMAL AND DEFINITIVE FIX ********************

So I finally got it fixed! This time for real and permanently:

After going through all the fixes mentioned at the OP, and of course going back to the OEM air box I decided to use my K+DCAN cable one more time (I was bored and wanted to "chat" with my DME and have a deep conversation on how much I hated my car at this point)...
So I loaded INPA
Selected 1 Series
Selected Gearbox
and I couldn't see my DCT transmission listed... if I select any other transmission (GS19 for example) I was getting an error message saying (No response from GS19 module. Your current module DSG_90)
So I decided to go directly to my INPA.ini editor and include the DSG_90 option manually.
Well.... boilá, I was able to finally get into the DSG (DCT or DKG) transmission menu through INPA!

So I was able to reset all the adaptations including clutches pressure levels, oil adaptation and even temperature adaptations.

Then I want back to the Engine menu and reset 2 things:
- Reset Throttle Adaptations
- Reset Air Pressure Adaptations

And then... BOOM!! Problem solved! No more throttle lag, no more RPMS fluctuation... no more issue.

SO here is my theory:
The Throttle Body was acting with a software based delay, so the transmission working with the tb was not coordinating in the correct time. Long story short: The thorttle body was opening later and closing later, generating a false vaccum and causing the stall on the car.

SO AS A FINAL CLOSURE, and I HOPE THIS HELPS TO ANYONE HAVING THE INFAMOUS DCT (DKG) PROBLEM RELATED TO THROTTLE RESPONSE AND RPMS FLUCTUATION AND STALL WITH AC ON:

Do this in this order:

- Make sure that you are not having boost or vaccum leaks.
- Took the car to the dealer for a software update (Mentioned the SIB 12 15 14)
- Use INPA to reset transmission and throttle adaptations (the dealership won't do this for you).

This is a SOFTWARE related issue.

-----------------------------------------------------------------------------------------------------------------------------------
Update June 28th 2017: Including exact changes to make at INPA settings/files in order to see the DKG_90 menu:

First of all make sure that you have an updated DATEN Files, in my case I was able to find the v60.2.
(Check this post and ask Wedge to PM you the zip file: http://www.e90post.com/forums/showth...170793&page=26)

Now, once you have the SP Daten files updated you need to go to the INPA.ini menu located at (EC-APPS\INPA\CFGDAT) and go all the way down and paste this:

Code:

[EXTRA]
SCRIPTS               = *
SCRIPTWECHSEL=DKG_90,D_EGS

Also update the E87 menu directly at the (EC-APPS\INPA\CFGDAT) directory and select the file: E87.ENG (if it is set to English language, or E87.GER if it's in german of course).
Then look for the Gearbox menu and include the DKG_90 line:

Code:

[ROOT_GETRIEBE]
DESCRIPTION=Transmission
ENTRY=    GS19,Gearbox Control Module GS19,
ENTRY=    DKG_90, DKG (Dual Clutch Transmission),

After this, save the files, go reopen INPA and the DKG Transmission menu should be there.

Hope this helps, please feel free to PM me if you have any questions.

Ganque

06-05-2016, 12:22 PM	#1
Ganque N55 Pure Stage 2 w/ DCT 23 Rep 49 Posts Drives: 2013 135is M Sport Join Date: Jun 2015 Location: Mexico iTrader: (0)	N55 with DCT RPMs fluctiation with AC On Finally Resolved! * N55 w/DCT issues resolved* Hey everyone! I've been having issues with my DCT when the AC was on for a while now... Months and months of research and I've finally found the solution! I've been having an issue with my car for a few months now, actually it started after installing my BMS Intake for the N55 engine. The car started to act weird whenever the AC is on and coming to a stop. I've been doing research for months trying to address this, and thinking that could be anything else but the BMS Intake. I checked on several forums in so many languages, most of them said that the symptoms matched with a Service Bulletin (SIB 12 15 14), and 99% of the times I posted my issue people replied back saying that this is a software issue and I should go to the dealer to get my DME updated.... I did it twice, and got charged for getting my DME updated twice because I'm out of warranty... So I've spend around $400 USD just trying to get this resolved by the dealership, of course no luck and still having the problem. Let me try to explain you the details on what was my issue: Symptoms: - Engine Stuttering at low RPMs when coming to a stop only with AC on. - Jerkiness Stalling with A/C - Car jumps forward when coming to a stop... it kinda feels like when doing a "heel-toe" downshift from 2nd gear to 1st gear including a knock noise from the engine fighting to keep it running on very low RPMs. - The car started to have these issues since I installed the intake, I did not touch the MAF sensor or anything else. Current mods on my car: - JB4 with ISO mod and JB4 connect kit - BMS Intake - Helix FMIC - Megan Racing Downpipe - Mid resonator deleted - COBB Chargepipe Actions already taken to attempt to fix the issue: - Took the car to the dealer for a software update (Mentioned the SIB 12 15 14) twice...... Didn't fix it - Did a DCT adaptations reset via Tool32 on a K+DCAN cable.... Didn't fix it - Did a Throttle Adaptations reset (regular pedal procedure)...... Didn't fix it - Updated my JB4 firmware to the latest version and switched to Map 5.... Didn't fix it - Regular oil change on the N55 engine.... Didn't fix it - Scanned the car for old codes... No codes saved - Checked for Boost or Vaccum leaks... No leaks found So after 5 months of just trying to live with this issue on hot summer days here in Mexico, I was even thinking on getting rid of the car... Someone in one of the million posts I made asking for a solution told me this: "It's your bms intake go back to stock intake problem solved" After all the issues that I've been going through I decided to switch back to the OEM Intake.... and that was it! No more fluctuation and jumps at low RPMS, holly cow. It's funny how I spent months on doing research, looking everywhere except for the intake. Now, the thing is, isn't this something that BMS should be aware of and warn the customers when ordering their products? Even if it's only under specific engine, transmission and mods, it still needs to be addressed, and I'd like to have a refund on my BMS Intake... or any other compensation, I now know that I can't have an intake on my car which sucks so bad. So in theory, the BMS Intake was getting more air during low RPMs which made the engine run lean at a certain point during the downshift from 2nd to 1st gear, so when the DCT tries to do the RPM matching action the RPMs are higher than expected. So after all this bible... here are the steps to perform when trying to detect and fix the issue: 1) Make sure the issue happens with a DCT (or DKG) transmission with the AC on. 2) If so, please check your current software version on your DME, if you don't have a K+DCAN cable or access to ISTA/D please take your vehicle to the dealership and ask for a software update. If you are out of warranty they will charge you somewhere ~$100-$200 USD to update it depending on the amount of modules your car requires an update. 3) If this doesn't fix your issue check your engine, if you have an intake, put back in the stock one and take it for a test drive. 4) If the issue is still happening, do a boost leak and vaccum leak test. 5) Depending on your milleage make sure to do service on your DCT every 30k miles. 6) Check for Spark plugs and coils. 7) Perform a LPFP and HPFP test. Hope this information helps anyone who might be having the same issue. Cheers! ********** UPDATE FOR OPTIMAL AND DEFINITIVE FIX ****************** So I finally got it fixed! This time for real and permanently: After going through all the fixes mentioned at the OP, and of course going back to the OEM air box I decided to use my K+DCAN cable one more time (I was bored and wanted to "chat" with my DME and have a deep conversation on how much I hated my car at this point)... So I loaded INPA Selected 1 Series Selected Gearbox and I couldn't see my DCT transmission listed... if I select any other transmission (GS19 for example) I was getting an error message saying (No response from GS19 module. Your current module DSG_90) So I decided to go directly to my INPA.ini editor and include the DSG_90 option manually. Well.... boilá, I was able to finally get into the DSG (DCT or DKG) transmission menu through INPA! So I was able to reset all the adaptations including clutches pressure levels, oil adaptation and even temperature adaptations. Then I want back to the Engine menu and reset 2 things: - Reset Throttle Adaptations - Reset Air Pressure Adaptations And then... BOOM!! Problem solved! No more throttle lag, no more RPMS fluctuation... no more issue. SO here is my theory: The Throttle Body was acting with a software based delay, so the transmission working with the tb was not coordinating in the correct time. Long story short: The thorttle body was opening later and closing later, generating a false vaccum and causing the stall on the car. SO AS A FINAL CLOSURE, and I HOPE THIS HELPS TO ANYONE HAVING THE INFAMOUS DCT (DKG) PROBLEM RELATED TO THROTTLE RESPONSE AND RPMS FLUCTUATION AND STALL WITH AC ON: Do this in this order: - Make sure that you are not having boost or vaccum leaks. - Took the car to the dealer for a software update (Mentioned the SIB 12 15 14) - Use INPA to reset transmission and throttle adaptations (the dealership won't do this for you). This is a SOFTWARE related issue. ----------------------------------------------------------------------------------------------------------------------------------- Update June 28th 2017: Including exact changes to make at INPA settings/files in order to see the DKG_90 menu: First of all make sure that you have an updated DATEN Files, in my case I was able to find the v60.2. (Check this post and ask Wedge to PM you the zip file: http://www.e90post.com/forums/showth...170793&page=26) Now, once you have the SP Daten files updated you need to go to the INPA.ini menu located at (EC-APPS\INPA\CFGDAT) and go all the way down and paste this: Code: [EXTRA] SCRIPTS = * SCRIPTWECHSEL=DKG_90,D_EGS Also update the E87 menu directly at the (EC-APPS\INPA\CFGDAT) directory and select the file: E87.ENG (if it is set to English language, or E87.GER if it's in german of course). Then look for the Gearbox menu and include the DKG_90 line: Code: [ROOT_GETRIEBE] DESCRIPTION=Transmission ENTRY= GS19,Gearbox Control Module GS19, ENTRY= DKG_90, DKG (Dual Clutch Transmission), After this, save the files, go reopen INPA and the DKG Transmission menu should be there. Hope this helps, please feel free to PM me if you have any questions. Ganque __________________ Last edited by Ganque; 06-28-2017 at 11:51 AM..
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