[DOCTOR.Y]

Hi guys,

I noticed that the car has a bit hesitation when starting to roll off red light. Basically when I release the brake pedal car almost won't move and then I foot on gas pedal, at the very first second it behaves as if it is hesitating to go or not. This feeling is completely different and noticeable from my previous E90 6AT, F30 8AT. For these cars if I release brake pedal it will move smoothly by itself. My DCT car also moves but just feel power is not delivered to wheels. I don't know if this is the feature of DCT?

Also in D gear, I have to almost open more than 50% throttle to let it downshift. In S gear it's more active in downshifting. But D gear is terrible, car just won't shift unless I open a wide throttle or kicked down. Anyway to reset DCT?

Thanks heaps

[raptor_f22]

Has it had a transmission and differential service at all?

[DOCTOR.Y]

Sorry forgot to mention car's condition. 2012 E92 335 51000km on the clock. No transmission service done yet.

[nojeans]

I've same feel since new

[Rob_BMW_PNW]

D sucks in general
I almost always have it in S

Maybe a software update

[Tricki]

You can drive in D, with sport button on as it sharpens throttle response and kick down earlier on the pedal .

[GreQonE]

I have just done transmission job at 39000 KM, from the looks of the oil filter I could say that it was about time.

Try doing that and see what happens

[maddmatth]

You need the DCT software and ECU update, certain older versions had some poor responsiveness. Just got to a dealer or specialist and ask them to update to the latest versions.
Mine was the same when I first got it, certain situations would be very unresponsive, as if it's paused for a second to think about which way to shift. After updating it's perfect, instantly kicks into gear when it needs to. Plain old D mode is perfect for regular driving since then.

Or just go straight to getting MHD flasher, it updates ECU as part of its setup process anyway(not transmission, but you might only need ECU update, in my case it was only the ECU update it needed).

51 000 km is very early for a DCT trans service, I'd leave it until 100 000km. It's not a regular auto, you won't see a different from such an early fluid change.
Although do check it isn't leaking transmission fluid, or get the shop to check it's ok, that's a fairly common issue.

[DOCTOR.Y]

Originally Posted by Rob_BMW_PNW

D sucks in general
I almost always have it in S

Maybe a software update

For a stock car, my understanding is D is designed to use the sole power from engine most of the time, so it gives the smoothest acceleration. S is designed to take more advantages of downshifting gears to give more punchy acceleration. Sports mode increase throttle response and lower one gear all the time when driving.
Overall my feeling is, D=smoothest but slowest acceleration, S=punch & sensitive; D+sport mode = less smoother than D(more downshift) but more responsive than D (one gear lower); S+Sport mode = restlessness.

[DOCTOR.Y]

Originally Posted by GreQonE

I have just done transmission job at 39000 KM, from the looks of the oil filter I could say that it was about time.

Try doing that and see what happens

Talk to local service guy, they said too early

[DOCTOR.Y]

Originally Posted by maddmatth

You need the DCT software and ECU update, certain older versions had some poor responsiveness. Just got to a dealer or specialist and ask them to update to the latest versions.
Mine was the same when I first got it, certain situations would be very unresponsive, as if it's paused for a second to think about which way to shift. After updating it's perfect, instantly kicks into gear when it needs to. Plain old D mode is perfect for regular driving since then.

Or just go straight to getting MHD flasher, it updates ECU as part of its setup process anyway(not transmission, but you might only need ECU update, in my case it was only the ECU update it needed).

51 000 km is very early for a DCT trans service, I'd leave it until 100 000km. It's not a regular auto, you won't see a different from such an early fluid change.
Although do check it isn't leaking transmission fluid, or get the shop to check it's ok, that's a fairly common issue.

Did you update ECU or TCU? I am about to go for MHD N55, but can I address TCU issue by only remapping ECU?

[maddmatth]

Originally Posted by Eric_Y

Did you update ECU or TCU? I am about to go for MHD N55, but can I address TCU issue by only remapping ECU?

It was only an ECU update in my case, and it made a major difference. I would guess the ECU communicates with the TCU to control shifting, or at least the data it sends would influence shifting behavior.

But if your TCU isn't up-to-date, it would be good to take care of that too.

Also another minor thing to note, sport mode (the sport button) does influence shifting too. Just hitting that, without moving the shifter over, does make the car use slightly more aggressive shift points, good for back roads where the full on "race track shifting" of DS mode is too much.
Personally I never use DS, it's either D or I go to manual sport mode.

[klipse]

There really needs to be a commercially available TCU flash for the DCT, that would open up a lot of possibilities I think. I think the guys doing xHP will be on top of this for the DCT crowd.

[DOCTOR.Y]

Originally Posted by maddmatth

It was only an ECU update in my case, and it made a major difference. I would guess the ECU communicates with the TCU to control shifting, or at least the data it sends would influence shifting behavior.

But if your TCU isn't up-to-date, it would be good to take care of that too.

Also another minor thing to note, sport mode (the sport button) does influence shifting too. Just hitting that, without moving the shifter over, does make the car use slightly more aggressive shift points, good for back roads where the full on "race track shifting" of DS mode is too much.
Personally I never use DS, it's either D or I go to manual sport mode.

got check my DCT software version But it`s build in 2012 and 2013 is the last batch of E92, didn`t sound like I have a very old version.... I agree DS is too much in normal street driving. D+Sports is quite good, if gear change can be more active. I tested several ZF8 F30, the logic is very linear. Less than 20% throttle = no downshift, 30% downshift 1; 50% downshift 2; 70 downshift 8 and so on.

[DOCTOR.Y]

Originally Posted by klipse

There really needs to be a commercially available TCU flash for the DCT, that would open up a lot of possibilities I think. I think the guys doing xHP will be on top of this for the DCT crowd.

Sorry can you explain a bit more ?

[rich_mane]

Just to add a little bit here, every M car that I've driven with the DCT doesn't move until you hit the gas. You can let off the brake at a stoplight and it won't move until you gas it. I haven't driven many of the 135/335 DCT but I remember that some creeped forward, some stood still.

[EB89]

Originally Posted by rich_mane

Just to add a little bit here, every M car that I've driven with the DCT doesn't move until you hit the gas. You can let off the brake at a stoplight and it won't move until you gas it. I haven't driven many of the 135/335 DCT but I remember that some creeped forward, some stood still.

Mine moves forward if you are in 1st gear without pressing the gas pedal. Although it does sit for around 3 seconds then you feel it engage the gear and start moving itself.

[maddmatth]

Originally Posted by rich_mane

Just to add a little bit here, every M car that I've driven with the DCT doesn't move until you hit the gas. You can let off the brake at a stoplight and it won't move until you gas it. I haven't driven many of the 135/335 DCT but I remember that some creeped forward, some stood still.

It creeps forward on the non-M cars, it's programmed this way, seems BMW thinks they should emulate a traditional auto for these models. Not as instantly like an auto, if you release the brake it gradually engages the clutch and starts creeping.

Not sure why BMW does it this way, IMO the forward creep that autos do is not a good thing so I wouldn't emulate it on a transmission that doesn't do this naturally.
It does make crawling in traffic a tiny bit more convenient though, you don't need to move your foot sideways every time the traffic crawls a bit, so it makes some sense.

[rich_mane]

The traffic bit makes sense, I can surely see it being more convenient that way. I was always a little confused as to why the same style transmission would perform differently between M and non-M. Mainly because the only cars with the DCT (at least over here in the states) are the 135is/335is variants that are supposed to be performance models anyways. But I'm sure they still want to separate them from the M models a little more.