[e90yyc]

Replaced the DSC unit. Problems solved.

Recently manual-swapped my 09/2006 build 328xi. Didn't cut a single wire and was meticulous about the install. Everything went perfectly but I'm having an issue that I believe relates to DSC.

Cruise control engages and disengages correctly (brake cancels it; clutch pauses throttle to allow for gear change), except when it's actually engaged the throttle surges on and off. This simply goes on and on. Sometimes I'll receive a cruise error but normally I've just stopped it right away because it's quite uncomfortable. To be clear, the car isn't applying full throttle at any point—the amount of throttle seems appropriate to reach or maintain the set speed—it just doesn't hold throttle. It's like a yo-yo.

Second issue feels identical to the one above but is triggered by me making a hard gear change under heavy throttle or driving over a bump under heavy throttle. Similar to above, the throttle seems to cut out and then toggle on and off. If I lift off the throttle then reapply, issue goes away... Not always but sometimes I'll see the DSC light flash for a few seconds, but my wheels aren't slipping.


Following is a summary of the coding/programming-related things I've done so far:

• Change VO to remove automatic and write this to CAS and FRM. Confirmed multiple times that the write was successful.
• Code factory settings to DME, DSC, CAS, FRM, KOMBI, etc... Also confirmed the coding is correct as far as I can tell (transmission type and other parameters I would expect to see changed for a manual trans vs. an auto)
• Flash DSC module using WinKFP
• Calibrate DSC and steering angle sensor using ITSA+

_________________________________

Other relevant info:

• I'm using xDelete, but have flashed back to stock using both the app and WinKFP which hasn't made a difference.
• Flashed DME back to stock multiple times; no difference
• No vacuum leaks (smoke tested three times now)
• Checked wiring at DSC module; looks good
• Start assist (no roll back on hill) does NOT work and didn't work even when I had my automatic.

Any ideas? TIA!

[e90yyc]

Bumping this up to include video and provide an update.

Relevant details since my last post:

• Flashed DME back to stock (had 330i software due to 3IM); no change
• Coded entire car to factory settings; no change
• Confirmed clutch switch operational; confirmed signals in INPA for both slight press (for cruise control) and full press (needed to start)

The only other variable that comes to mind is my FRM2 module retrofit. I've looked at BMW technical docs and it appears FRM's only role in DCC system is to illuminate brake lights when dynamic braking is needed to maintain set speed... Regardless, I'm going to swap my FRM1 module back in during the coming days to see if it makes a difference. (I doubt it will.)

I was also having issues with my JBBF module not appearing in ISTA+ (which gbalthrop kindly helped me sort through), but all the evidence indicates this is just a gremlin and is definitely not causing my issues.

I've done some research into the DCC system which I can recount if necessary, but to keep this post shorter I won't get into it unless asked.


It's very obvious while driving it, but in the video you can see what I'm feeling by looking at the MPG gauge... It's like the DME is confused about how much torque to request. But given the fact the car is also cutting throttle sometimes even at random, it's obviously something that affects more than just the cruise control...

Really at a loss here as to what to do. If anyone can help even with a very general troubleshooting procedure, it would be greatly appreciated. I think I need to get back to the basics here.

[KClemente]

I've done multiple manual swaps on N54's but I'll try to help.

Have you gone into INPA and reset the "variant adaptation" in your dme? Coding is one thing, but resetting the variants tells the DME to relearn what it does and does not have (auto vs manual).

Now (at least on N54)the tune files between manual and auto are exactly the same so that will not have any effect.

Also in your DME box, did you disconnect the canbus wires (2 twisted pairs; 4 wires total) from the black plug and merge the corresponding colors and stripes together?

Sudden throttle cut and especially surging is a sure sign that the DME still thinks it's got an automatic transmission and using different torque request configuration

[e90yyc]

Originally Posted by KClemente

I've done multiple manual swaps on N54's but I'll try to help.

Have you gone into INPA and reset the "variant adaptation" in your dme? Coding is one thing, but resetting the variants tells the DME to relearn what it does and does not have (auto vs manual).

Now (at least on N54)the tune files between manual and auto are exactly the same so that will not have any effect.

Also in your DME box, did you disconnect the canbus wires (2 twisted pairs; 4 wires total) from the black plug and merge the corresponding colors and stripes together?

Sudden throttle cut and especially surging is a sure sign that the DME still thinks it's got an automatic transmission and using different torque request configuration

THANK YOU so much for the response. Really appreciate the help.

I've reset ALL adaptations multiple times (and have flashed between stock 328 DME firmware and 330 "tune" firmware), but just to be sure I went back in and reset Variant Adaptations specifically. Don't have time for a test drive at this moment but I will report back.

As for the DME box, I know exactly which plug you're referring to, and indeed I made sure to join the canbus wires. I would also expect to see errors galore if I had an open canbus loop. TBH, I'm confused by a lack of error codes overall. This makes me think it isn't something like a wheel speed sensor or some other sensor that would throw a deviation code if it was out of range.

I'm glad you agree about the DME thinking it's automatic. I just don't under HTF (how the fuck) that's possible when I've quadruple-checked my coding and programming, and everything works on a surface level as it should.

At this point, maybe someone with a manual-transmission xDrive 328 can share a few of their trace files with me so I can compare them to what I have. That would be much appreciated!!!

[mad1stgen]

Did you clear vehicle equipment options in INPA ? Take a screen shot of options as of right now.

[e90yyc]

Originally Posted by mad1stgen

Did you clear vehicle equipment options in INPA ? Take a screen shot of options as of right now.

Hey, thanks! I was actually just thinking of you as I know you've done a bunch of these.

Could you please clarify which module vehicle equipment options are cleared on? I've cleared adaptations probably five times now on DME, but perhaps I've missed doing what you describe. Once I know that I'll grab a screenshot.

TIA

Edit: Fairly certain I found what you're referring to. I've attached the results. A few things stand out:

• Longitudinal dynamics management (my 09/2006 build was the first prod month they did away with the LDM module in the sedan)
• Electric steering and no air conditioning (irrelvant to my issue I'm sure, but weird...)

[mad1stgen]

That's the page. And it looks correct. Don't worry about the ele steering.

Any ISTA codes ? What does the module tree look like ?

[e90yyc]

Originally Posted by mad1stgen

That's the page. And it looks correct. Don't worry about the ele steering.

Any ISTA codes ? What does the module tree look like ?

Thanks.

No codes other than e-box code that was there before the swap (because I removed it).

For some strange reason my JBBF module doesn't appear on the tree, but again, this issue was there before the swap and is more likely related to my ISTA+ install and not my car. JBBF shows up everywhere else: INPA, ISTA/P, etc...

The EGS does appear on the module tree (in red, obviously).

[mad1stgen]

Lack of JBBF worries me. A lot. Red EGS is normal (it's hardcoded).

Read values from each ABS/speed sensor are you drive when it's acting up. Maybe that'll shed some light ...

[mad1stgen]

Now that I looked at your video again, I had a car that did this after a conversion. It had a huge vacuum leak from the TB inlet accordion tube not sealing properly.

[e90yyc]

Originally Posted by mad1stgen

Now that I looked at your video again, I had a car that did this after a conversion. It had a huge vacuum leak from the TB inlet accordion tube not sealing properly.

You're referring to the plastic tube that attaches to TB via hose clamp, ya? If so, would the implication here be that unmetered air is getting past the MAF?

I ask because I'm currently running a 3-stage IM and have a no-MAF "tune" from the 330. But during this whole process I went and flashed stock firmware back and didn't seem to be any different.

I've been having idle issues (high idle and a bit of surging on cold start) so a vacuum leak would make sense. I have done a few smoke tests though with no obvious vacuum leaks, but I sealed the tester hose to the hard tube that comes right off the TB so the accordion tube wasn't part of the equation.

Worth noting is that when using DCC it struggles mainly with maintaining speed and small speed increases; large-increment increases seem to elicit better throttle response. I am also getting weird throttle cut and surging if I make a really hard shift, though it doesn't seem to happen if I have DSC off.

Originally Posted by mad1stgen

Read values from each ABS/speed sensor are you drive when it's acting up. Maybe that'll shed some light ...

Was thinking this same thing, but is there a better way to do this than just using INPA? Ideally some way to graph or record this data without going and buying extra hardware?

Originally Posted by mad1stgen

Lack of JBBF worries me. A lot.

Hmm, any suggestions? I'm going to try re-installing ISTA and go from there. Only reason I haven't worried too much is that it still shows up everywhere else, and I'd expect major major issues if something as critical as JBBF weren't communicating.

Thanks again for your help, I really appreciate it.

[e90yyc]

Ughhh not being able to solve this is getting really old.

Updates:

• Observed readings from wheel speed sensors during issue. All normal.
• Observed readings from longitudinal and other acceleration sensors. All normal.
• Flashed DME to 330i software WITH MAF. Didn’t know this but apparently cruise doesn’t work with the no-MAF tune, although my personal experience says otherwise. (Worked flawlessly when I had the auto in there. Guessing it’s just possible it won’t work which is why there’s the disclaimer.)
• Start (hill) assist does not work but is coded to be enabled. I can worry about that later; just mentioned in case it’s related.

So, when I enable cruise, after a few seconds of lumpy throttle I’ll usually get the cruise deactivation symbol. Attempting to reactivate cruise doesn’t work UNLESS I press the clutch in all the way in which case it lets me reactivate it. Clutch re-engagement is smooth—it’s clear the DME knows the clutch is not yet fully engaged—but after half a second after releasing it the throttle jolts on and then cruise usually errors out.

[e90yyc]

Another update:

Installed new version of ISTA; JBE module now appears. (gbalthrop—not surprisingly, you were correct about it being a software issue )

Looks like I can definitively rule that out as an issue.

[hassmaschine]

Might be worth getting a copy of testo, or maybe protool, and do some logging. Without any codes, it's really hard to help otherwise

There's also the possibility of disabling the DSC input into the DME, just to rule it out as an issue.

[e90yyc]

Originally Posted by hassmaschine

Might be worth getting a copy of testo, or maybe protool, and do some logging. Without any codes, it's really hard to help otherwise

There's also the possibility of disabling the DSC input into the DME, just to rule it out as an issue.

THANK YOU for the input. I need any/all help I can get at this point because I've done so much troubleshooting already and am baffled.

• When you say disable DSC input into DME, I take you're referring to something other than just using the DTC button? If so, is this something I could do or would this be too complex?
• I'm going to look into Testo. Protool would be great except I don't have an Android phone...
• Is there any way that xDelete could be causing this issue? I used the "flash back to stock" function in the app and didn't seem to change the issue, but I might try to flash the module back to stock using WinKFP instead.

BTW, this is the only DTC I've ever gotten related to this issue...

[hassmaschine]

it's a setting in the DME, it has to be flashed - you can disable ASC/DSC torque reduction requests. If the DSC was sending a bad signal, that could be it.

I wouldn't rule out something like a vacuum leak or maybe bad DISA valve though. I wouldn't think xdelete would do anything, but I've never really used it personally.

[e90yyc]

Originally Posted by hassmaschine

it's a setting in the DME, it has to be flashed - you can disable ASC/DSC torque reduction requests. If the DSC was sending a bad signal, that could be it.

I wouldn't rule out something like a vacuum leak or maybe bad DISA valve though. I wouldn't think xdelete would do anything, but I've never really used it personally.

I’ve smoke tested the car about three times now and can’t find any vacuum leaks. DISA valves are basically new (BMW) and working great.

You know, I think I have a theory based on my experience with removing my front driveshaft a while back. (Just to be clear it’s since been reinstalled. I’m also going to just refer to it as the driveshaft from here forward.)

When I had the driveshaft out the car worked fine, except when I’d hit corners hard and the wheels started to slip just a bit. In those cases, power would cut as the car thought it was sending torque to the front when in fact there was none being sent at all. Once I got xDelete (when the car was still an auto), the sudden power cut was no longer an issue.

I just got back from a trip during which I experienced a few spontaneous power cuts, but I started to put the pieces together.

• Happens when I make a very hard shift at high RPM
• Happens when I’m hard on the gas and hit a bump
• Happens when I engage cruise control, regardless of any other factors

The common denominator here is that front and rear wheel speeds are just slightly different, often for just a split second. Both the bump and hard shift are easy to understand: there is a tiny bit of slippage just for an instant with the rear wheels, and the car gets confused. For the cruise, I think the car is expecting both front and rear axle speeds to increase at the same time, but again… with no torque going to the front, there’s a deviation from what’s expected, just for a split second.

Let me know what you think of this theory. For now I’m going to try to flash the transfer case entirely back to stock using WinKFP.

[e90yyc]

Originally Posted by hassmaschine

it's a setting in the DME, it has to be flashed - you can disable ASC/DSC torque reduction requests. If the DSC was sending a bad signal, that could be it.

I wouldn't rule out something like a vacuum leak or maybe bad DISA valve though. I wouldn't think xdelete would do anything, but I've never really used it personally.

Good news: I have error codes, and lots of them. I don't know why all of these suddenly appeared. Also, my theory about the VGSG and xDelete doesn't seem to have panned out. I tried flashing transfer case back to stock and cruise was still doing the same thing...

BTW, I know the beauty of these forums is that we help each other for free, but I'm willing to throw some thank-you money someone's way if they're able to help me sort this out.

I've installed Testo and have it working in a basic fashion. Most of the functions are in German (for MSV80) which sucks and is making figuring out what is what quite hard. I'll update you once I figure out how to log the data I need.

Please see DTCs below. I've also attached PDF of the error codes, as well as an Excel spreadsheet (in zip file) with the same.

TIA!

[gbalthrop]

What Cruise Control Option does your vehicle have? Active Cruise Control? I know this sounds strange when you have INPA & ISTA, but do you have CC-ID code 1, 2 or 3?

You MAY have an incorrect Setting selected in the DSC module, and the Cruise may be cutting out due to NO/ Faulty Distance Sensor Signal.
Just a SWAG.
George

[e90yyc]

Originally Posted by gbalthrop

What Cruise Control Option does your vehicle have? Active Cruise Control? I know this sounds strange when you have INPA & ISTA, but do you have CC-ID code 1, 2 or 3?

You MAY have an incorrect Setting selected in the DSC module, and the Cruise may be cutting out due to NO/ Faulty Distance Sensor Signal.
Just a SWAG.
George

Hey George,

Thanks for the help!

No CC-ID messages. I just get the cruise control error with the speedometer graphic and exclamation mark a few seconds after I enable cruise.

I have option 544 - Dynamic Cruise Control (with braking).

Apparently all ACC cars have the LDM module, which my car definitely does not have. I'll take a look at my DSC module coding. Also going to re-check all the wiring, but the nature of my issues don't point to faulty wiring IMO.


hassmaschine I've got TestO up and running. Can you let me know what I should be logging? I'm finding the lack of translations (overall) challenging, plus my relative lack of knowledge in this area.

Once I know what to record, I'll do a bunch of logging and report back.

[e90yyc]

Another update:

The only code that consistently appears is 6E12 — DSC: Sporadic DCC fault: No repair measure necessary

As the title implies, I'm willing to pay someone as a thank-you for help solving this. I've done so much research and so much troubleshooting at this point, I'm at the limit of my knowledge/skills.

• Wheel speed sensors appear to be reading correctly. I haven't figured out how to actually log this data so until then all I can do is screen record. I've done a bunch of this already and don't see anything unusual, but I do need to actually log this data to be sure.
• Start-assist (prevents roll-back on hills) function does not work despite being coded on by default. It actually didn't work when I had the auto transmission either, which it should have. From what I understand this feature will not function if there are issues with wheel speed sensors, and probably DSC sensor too.

Video 1

When driving with cruise on, engine torque yo-yos. I'm not touching the throttle. You can also see a small fluctuation in RPM. This always happens with cruise. For some reason when idling or off the throttle, torque shows as about 2000 Nm, but not sure if this matters.

Video 2

When driving with cruise on, you can see the DSC pump blipping brakes on and off (spike in pump motor voltage), which can also be heard and felt from the cabin. This happens only sometimes.

1. Is it possible I have a bad wheel speed sensor despite there being no codes?
2. What about bad DSC sensor (under driver seat)?
3. What the hell else could I check?

[hassmaschine]

Sorry, I have been busy with work trying to finish up a project - have you tried default coding the DME? 6BM0T in NCSExpert - there are various guides online. It'll make the "no coding" error go away. It doesn't affect the DME, and I've never heard it affect other modules, but maybe the DSC is confused because you switched from AT to MT.

Based on your other errors - no message errors - that means, it's expecting CAN messages. I assume from the EGS. So for some reason your DSC hasn't fully accepted the coding from AT to MT.