Strange but seemingly new DCT issue

[ihyln]

So today I'm on my way home for lunch and I'm on a noticeable incline going down it. I rolled through the yield sign in 2nd gear maybe at about 20mph (no one coming from the other direction) and I click to downshift to have a little fun... But theres no downshift! Now I turned onto the road and I stomp on the gas but there's no power! I check my RPM and I'm at about 1200-1300. My car limps along on my momentum as I stop to pull over to the side. I stop to go WTF and I'm back on my merry way.

First time this ever happened. Whatever that is going on is overriding the user's intentions so I'd have to say this problem is definitely software related.

[JIO]

Thanks...maybe we need to have a special section of problems people are having with M DCT so we can show it to BMW or let them read about the problems. I'm sure the problems are software related. I remember my SMG E46 M3 had several software updates.

[masmole]

Yes, and all those with DCT going in for their 1200 mile service. Make sure you stress your concerns with about stalling, quirks, other issues whether major or minor regardless of whether it only happened once and did not surface again, happens occasionally, or frequently. Hopefully this will get the ball rolling sooner in terms of getting a software fix out.

Personally, I've only had it stall once, last week with 200 miles on the odo, and it never happened again. But I'm going to stress to the service department that it happened at an intersection and although no harm was done, it could potentially be a serious safety issue if it happens under different circumstances.

[!Xoible]

wait, u were rolling at 20 mph in 2nd gear and wanted to shift down into 1st gear? is this what you were trying to do?

[Captain Scott]

Originally Posted by ihyln

So today I'm on my way home for lunch and I'm on a noticeable incline going down it. I rolled through the yield sign in 2nd gear maybe at about 20mph (no one coming from the other direction) and I click to downshift to have a little fun... But theres no downshift! Now I turned onto the road and I stomp on the gas but there's no power! I check my RPM and I'm at about 1200-1300. My car limps along on my momentum as I stop to pull over to the side. I stop to go WTF and I'm back on my merry way.

First time this ever happened. Whatever that is going on is overriding the user's intentions so I'd have to say this problem is definitely software related.

I had the same thing happen to me on the car that I returned.

My car however also stalled, and had the transmission malfunction Light as well.

IT'S A SOFTWARE PROBLEM

Scott

[ihyln]

Originally Posted by ///Mantis

wait, u were rolling at 20 mph in 2nd gear and wanted to shift down into 1st gear? is this what you were trying to do?

Yes, I wanted to go into first.

[!Xoible]

Originally Posted by ihyln

Yes, I wanted to go into first.

coming from manual i would say it's by design. u probably would have broken the gear box going in 20 in first gear. i dont think it should let u, in fact im hoping it's designed not to let you. this seems to be protecting ur drive train and gear box

[ihyln]

I am estimating my speed, I THINK I was going 20 but I had to slow down because of the yield sign. I may have been doing less but definitely not more than 20.

[!Xoible]

usually if the car is rolling u dont want to go in first. if around 10 mph or more im sure u dont want to shift into 1st (speaking in terms of manual anyway)

[ihyln]

Ah I see. Then if that's the case I understand. However, I don't know why I was not able to get power out of the car afterwards.

[BMWDEMON]

probably software but I agree with Mantis, you probably are being hindered to go into first gear as a downshift...you would not want to do that, second gear is low enough...come to a stop, go into first for take off or slightly bump your RPM's in second and continue on your way...the car has plenty of power to do it.

M

[!Xoible]

Originally Posted by ihyln

Ah I see. Then if that's the case I understand. However, I don't know why I was not able to get power out of the car afterwards.

it probably thought it was doing something bad for the car so needed to reset something, or needed to put u in limp mode to protect itself. who knows. too much technology = too much intrusion sometimes. idk... im sure Swamp2 has some input for us

[Captain Scott]

Originally Posted by BMWDEMON

probably software but I agree with Mantis, you probably are being hindered to go into first gear as a downshift...you would not want to do that, second gear is low enough...come to a stop, go into first for take off or slightly bump your RPM's in second and continue on your way...the car has plenty of power to do it.

M

You guy's are correct with the exception that when you push on the gas even in 2 nd the car should do something.
I think what he was trying to say was, like me, that the car did not respond to any throttle input when he gave it some throttle (NONE) NO RPM increase.

Just my 2 cents

[Big Windy]

i don't think 20 mph should be an issue for 1st gear. do you think it prevented it because the rpm at that speed in 1st gear would have exceeded the redline?

[ihyln]

The thing is I've downshifted into first many times before at around the same speed. I think the only difference this time was that I was turning slightly and had some force on the brake pedal.

[TLud]

Originally Posted by Captain Scott

Yoy guy's are right with the exception that when you push on the gas even in 2 nd the car should do something.
I think what he was trying to say was, like me, that the car did not respond to any throttle input when we gave it some throttle (NONE) NO RPM increase.

Just my 2 cents

Sounds like the computer intervention (correctly preventing him from downshifting from 2nd to 1st gear at 20 mph -- you'd never do that in a manual) induced some sort of software glitch afterward. My thinking is that the DCT computer correctly prevented you from shifting down, but some other routine or part of the computer accepted your input and incorrectly treated the car as being in 1st gear and wouldn't accept the throttle input because it wouldn't let you "over-rev."

I'm not trying to criticize any DCT owners' driving abilities, but various posts that I've read on this forum suggest that some DCT owners forget that they're still essentially driving a manual transmission.

[ihyln]

I should clarify, I didn't stomp on the pedal immediately, after I noticed it didn't downshift I thought "o well" and I gave it a bit of gas but nothing happened, then I gave it more, and then I stomped on it and went "what the hell".

No offense taken about my driving abilities. I will happily admit that I am a novice w/ manuals.

[Captain Scott]

Originally Posted by TLud

Sounds like the computer intervention (correctly preventing him from downshifting from 2nd to 1st gear at 20 mph -- you'd never do that in a manual) induced some sort of software glitch afterward. My thinking is that the DCT computer correctly prevented you from shifting down, but some other routine or part of the computer accepted your input and incorrectly treated the car as being in 1st gear and wouldn't accept the throttle input because it wouldn't let you "over-rev."

I'm not trying to criticize any DCT owners' driving abilities, but various posts that I've read on this forum suggest that some DCT owners forget that they're still essentially driving a manual transmission.

I have down shifted from 2nd to 1st many times with my MT cars at 20 mph not even close to red line, it depends on the gear ratio.

With the M3 I can't recall now because I only had my car for a few hour's but,
with a red line about 8300 rpm or so and gentle throttle input it should be no problem getting the car to down shift to first even with the DCT.

If I had my car now I would go give it a try and see what happens! Anybody care to take a ride around the block and see what happens. you won't hurt anything.

Let us all know if anybody try's

[sayemthree]

dont feel bad - that happened to me in my MT. then I realized I had it in 4th gear and not 2nd. almost stalled it. its just part of the experience.

[TLud]

Originally Posted by Captain Scott

I have down shifted from 2nd to 1st many times with my MT cars at 20 mph not even close to red line, it depends on the gear ratio.

With the M3 I can't recall now because I only had my car for a few hour's but,
with a red line about 8300 rpm or so and gentle throttle input it should be no problem getting the car to down shift to first even with the DCT.

If I had my car now I would go give it a try and see what happens! Anybody care to take a ride around the block and see what happens. you won't hurt anything.

Let us all know if anybody try's

I'm too lazy at the moment to calculate what RPM 20 mph would be in first gear on the DCT, but you're right, it shouldn't be close to redline (it would be in many cars that I've driven). Some manuals I've driven wouldn't even let you push the stick into first at that speed.

[grayshrk]

I'm not sure I understand the issue with downshifting to first at 20mph. Why would that be an issue? It certainly doesn't over-rev the engine. It's been a while since I've had a MT but I don't remember any rule about downshifting only to second, and then only shifting into first while stopped completely. And as for whether or not you can downshift to first from second at 20 mph with DCT, yes you can. I've done it often with mine. If there really is a technical reason why you shouldn't do this, please post some details because I'd rather not do damage to my tranny.

[Captain Scott]

Originally Posted by TLud

Some manuals I've driven wouldn't even let you push the stick into first at that speed.

Very true statement, depending on the speed and RPM in which you try!
Whenever you get a chance would you mind try down shifting from 2nd to first at 20 mph and report your findings?

Over and Out

The Captain