[Benhum5]

So....

Over the past couple of weeks I have noticed something odd going on with the car: (2011 N55 DCT e92)

pulling out of a junction, full auto mode, probably changing form 1st to 2nd around 3-4k rpm and the whole car seems to pause for a second after the gear change, feels like quite heavy engine braking for about a second then back on accelerating.

This happened a couple of times so I did a bit of reading on forums and the majority of threads I saw about DCT and laggy moments were saying its driving habits that need to change to adapt to the different gearbox. I get that and see that it is relevant for the 'braking to a roundabout then accelerating before you've completely stopped' situation when the car disengages gear then needs to re-engage quickly. But in this situation I don't think that is the case, I have had the car a year and never noticed this before.

I have since noticed that sometimes in 2nd gear and manual mode (no gear change just before) that sometimes there is the same pause of about a second after trying to accelerate and anything actually happening. Almost like there is no boost for a second.

Neither of these things are happening often enough to be easily repeatable to a garage/knowledgeable person

Has anyone experienced anything like that or have any ideas what it could be?

There are no warnings on the dash and its not the traction control cutting the power as it can happen under barely any acceleration at-all and on a smooth/dry road. I am not in possession of a fault code reader at the moment but could probably get hold of one off a friend at work if needed.


Many thanks for any help

Ben

[mare92]

Originally Posted by Benhum5

So....

Over the past couple of weeks I have noticed something odd going on with the car: (2011 N55 DCT e92)

pulling out of a junction, full auto mode, probably changing form 1st to 2nd around 3-4k rpm and the whole car seems to pause for a second after the gear change, feels like quite heavy engine braking for about a second then back on accelerating.

This happened a couple of times so I did a bit of reading on forums and the majority of threads I saw about DCT and laggy moments were saying its driving habits that need to change to adapt to the different gearbox. I get that and see that it is relevant for the 'braking to a roundabout then accelerating before you've completely stopped' situation when the car disengages gear then needs to re-engage quickly. But in this situation I don't think that is the case, I have had the car a year and never noticed this before.

I have since noticed that sometimes in 2nd gear and manual mode (no gear change just before) that sometimes there is the same pause of about a second after trying to accelerate and anything actually happening. Almost like there is no boost for a second.

Neither of these things are happening often enough to be easily repeatable to a garage/knowledgeable person

Has anyone experienced anything like that or have any ideas what it could be?

There are no warnings on the dash and its not the traction control cutting the power as it can happen under barely any acceleration at-all and on a smooth/dry road. I am not in possession of a fault code reader at the moment but could probably get hold of one off a friend at work if needed.


Many thanks for any help

Ben

I am experiencing the same issue on my E93 2012 with DCT. The only thing that helped was to reset all of adaptations and, but the problem came back after a month. I have the latest firmware for just about everything in my car, did a full preventive service on DCT about a year ago, the dealer can't find any problem on transmission, but it is just not pleasant to drive.
The only thing I haven't tried is the new XHP DCT flash, but it is really expensive(450$/400€).

[Benhum5]

Originally Posted by mare92

I am experiencing the same issue on my E93 2012 with DCT. The only thing that helped was to reset all of adaptations and, but the problem came back after a month. I have the latest firmware for just about everything in my car, did a full preventive service on DCT about a year ago, the dealer can't find any problem on transmission, but it is just not pleasant to drive.
The only thing I haven't tried is the new XHP DCT flash, but it is really expensive(450$/400€).

Yes you are right about it not being pleasant to drive. It seems like there are mixed opinions as to whether the software updates cure it or not. Currently trying the ‘turn the air-con off’ method which seems to be the case that it is better with it off but haven’t driven enough to be sure yet, and then need to read up what that actually means might be happening.

There seems to be loads of different things people have done and ‘solved’ the problem it doesn’t seem like there one definitive fix which is strange.

[Benhum5]

Quick update from me, have measured my battery voltages as I saw a post about someone getting rid of the issue by replacing their battery. With car running it is 14.9v and car off 12.3V - nothing strange going on there really then

The problem definitely seems better when the AC is off

The other thing I have noticed is that my cooling fans seem to be coming on whenever the car is stopped, this is happening right from the start of driving with the engine not even fully warmed. Could be a dead thermostat somewhere?

Local BMW dealer have said they can read the software version on the gearbox if I take the car in and let me know if there is an update so I will do that and see what is said

[ferocity02]

AC on is known to cause the DCT to act a bit funny, especially taking off from a stop. Give XHP a try, I flashed stage 2 yesterday and it did smooth out D a little bit. If 0 is clunky as hell and 10 is dont feel the shifts at all, XHP moved it from a 7 to an 8 for drive mode daily driving. XHP will also reset adaptations.

[Benhum5]

Here's the problem (well its a problem, but slowly losing oil would explain it slowly getting worse.) DCT oil Sump leaking.

looks like a previous owner tried to get it fixed on the cheap with some sealant too! I'm surprised its lasted the year I've owned the car before becoming a problem. Booked in to be replaced on Friday so we will see what it's like after that. They said there is a software update available too but its best to get this done and see what happens first.

[E92only]

I drive a manual N55 and experience the same issue with the AC on. My shifts are sluggish no matter how well I shift the gears. Downshifts? Forget it with the AC on. Good thing my condenser broke. Windows down in July for me. Socal btw

[Benhum5]

Can now confirm Sump replacement didn't solve the problem, car feels like it changes better but still has the same lag issue.