DSG Reset (Basic Settings)

[k.young]

Oh no.........look what I've started!!!!!

 

 

So, for the avoidance of doubt.......mechanical sympathy prevents me from putting my car into 1st while moving.

[Gammyleg]

Without wishing to hijack this thread, I'm having trouble accessing expected screen options for a clutch reset/adaptation using my VCDS.

 

I get as far as Selecting Control Module > 04 Basic Settings > at which point I should get a drop down box with options such as ' 02294 Main Pressure Valve Calibration',  ' 02295 Clutch Valve Calibration' and '02298 Clutch Engagement Point Adaptation' amongst others. Unfortunately I get none of these.

I've queried this on RossTech forum but answers have not been particularly useful. It appears that many of the tutorials are based on old tech versions of the VCDS whereas my modules use UDS protocol ( whatever that is )

 

If anyone has successfully carried out or could advise as to how I can perform a clutch reset on a DQ200 with UDS protocol transmission I would be eternally grateful.  

 

Screenshot below is as far as I've got. Could anyone suggest which options I should select and what I might expect to see /experience when I do?

 

Additionally, should the engine be running when these adjustments are selected?

 

 

 

Edited 4 March, 2023 by Gammyleg
screenshot added

[j caff]

23 hours ago, Donweather said:

Ok fair to say there’s differences of opinion on this which I appreciate everyone’s opinions. But for those who believe the gearbox isn’t designed for downshifting from 2nd to 1st unless you’ve come to a complete stop just try the following. 
 

Throw the DSG into sport mode. Drive in S2 at around 3000rpm (which is around 40km/hr). Dump your right foot on the accelerator. What happens. DSG downshifts under full throttle to S1 jumping up to around 4000-4500rpm under full torque from the engine. 
 

now which scenario is putting more strain on your gearbox. The one above or downshifting from 2nd to 1st under engine compression braking. 

Try driving a vintage car with no synchromesh, going up through the gears is easy, coming down is extremely difficult. The internal clutches are trying to do this when you command it to drop from second to first. 

[numskull]

On 04/03/2023 at 00:26, Donweather said:

now which scenario is putting more strain on your gearbox. The one above or downshifting from 2nd to 1st under engine compression braking. 

🙄 It’s downshifting to 1st of course, because that is just not what 1st gear is designed to do. You get a massive crash and huge reverse stress on the clutch pack and all the gearbox and drive chain system. On top of that, I’ve found there’s sod-all engine braking in modern ICE vehicles anyway, including our 280. But it’s your car, your choice.

[J.R.]

12 hours ago, j caff said:

Try driving a vintage car with no synchromesh, going up through the gears is easy, coming down is extremely difficult. The internal clutches are trying to do this when you command it to drop from second to first. 

 

You do not appear to understand the operation of a DSG twin layshaft gearbox.

 

In the instance of a downshift to first gear the first gear is pre-engaged on the free running layshaft, the gearshift happens seamlessly with the synchronised disengagement of the clutch on the 2nd gear layshaft and the engagement of the one on the first gear layshaft.

[J.R.]

3 hours ago, numskull said:

🙄 It’s downshifting to 1st of course, because that is just not what 1st gear is designed to do. You get a massive crash and huge reverse stress on the clutch pack and all the gearbox and drive chain system.

 

Another who does not understand how a twin layshaft DSG gearbox works.

 

Vehicles have not generally used chain drive transmissions since the days of Frazer Nash.

[MarkyG82]

1 hour ago, J.R. said:

 

You do not appear to understand the operation of a DSG twin layshaft gearbox.

 

 

Do you know if the box knows to select 1st instead of 3rd if engine speed is around 2k revs? Swapping to the other shaft is a smooth process but if wrong gear is selected it can be rough.

I know that when cruising (eg in 4th) then 5th might be selected on the other shaft but putting your foot down will change that selection to 3rd even if it doesn't swap to the other shaft. 

[J.R.]

It's predicted with algorithms in the way that you describe, accelerating through the gears on a light throttle it will preselect the next one up, if you brake then after the speed has fallen to the threshold it will preselect the lower gear, if you put the throttle to the floor and the revs are not too high it will again preselect a lower gear to "kick down", this by it's nature and the urgency (how fast you open or close the throttle is monitored) will be more of a kick in the back as thats what you are asking for.

[MarkyG82]

But will it select 1 or 3 if slowing in 2 with engine at 2k revs as per this post breaking gearboxes? Just wondering if making it panic into a shift it's not prepared for is adding to the stress and not helping the situation.

[J.R.]

To avoid me reading through 4 pages of a thread only to perhaps find that it makes no mention of DSG gearboxes breaking due to downshifts from 2nd to 1st gear can you quote the relevant text please?

 

To answer your question the DSG microcontroller does not have a nervous system, unlike some humans it will not become panicked or stressed through being unprepared for an event. It is always prepared to either upshift or downshift according to the circumstances, OK it can't upshift from top gear or downshift from 1st gear.

 

I speak of it being a pre-select gearbox but this could actually be during a very short time interval during shifting, it may well be that when cruising at a steady speed in say 5th gear on layshaft 1 no synchro hubs are actually engaged on layshaft 2, it could take place at the gearchange point (as the first stage) once it has been decided by the ECU, I have not read the self study guide, I simply understand how the system works (unlike some it would seem) and not the finer details.

 

Whether it pre-engages ahead of a gearchange or during would depend on the speed that the gearchanges are made, the faster the gearchange change required say on a Bugatti Veyron in sport mode the more likely to be pre-engaged ahead of time because of the inertias involved and the synchromesh loadings.

[Ootohere]

In the past 20 years and from Euro 4, 5 & 6 emissions and getting near to Euro 7 and more electric motors involved there has been very different behaviours with the various 

semi Automatic gearboxes / DSG's.

All sort of engine & gearbox management over the years including defeat devices used by VW Group. 

 

[MarkyG82]

On 02/03/2023 at 01:33, Donweather said:

Sportline 206TSI (280 BHP). DQ250 DSG. 
 

I downshift from 2nd to 1st when the car is still moving. It’s known as compression braking. Letting the engine do the work. 
 

if the gearbox isn’t designed to do this then VAG need to not allow it in manual/paddle mode. 
 

one has to remember that the 1st gear ratio on the DSG isn’t as small as a manual gearbox (ie I never changed down from second to first in my last manual Octavia vRS as you’d end up being ejected through the windscreen due to the manual gear box low first gear ratio). 
 

it’s not like it redlines when I downshift. Might go from 2000rpm in second to 3500-4000rpm in first. 

@J.R. this one.

 

10 hours ago, J.R. said:

, I simply understand how the system works (unlike some it would seem) 

 

 

 

No need for that. We're all trying to learn here.

Also, a mechanical system can most certainly be stressed. Under dynamic loads, an assembly of components can respond in unpredictable ways. Even if the logic controller allows something to happen it doesn't necessarily mean it should.

[J.R.]

As someone who spent many years doing stress analysis of dynamic mechanical systems I can tell you that the response of materials even anisotropic ones to applied load is entirely predictable.

 

The worse thing that can happen to any gearbox is to simultaneously select 2 gears at speed (through a worn or broken selector mechanism), a manual gearbox will turn into shrapnel, a DSG gearbox would strip one or both clutches leaving the geartrain intact, unless 2 gears were selected on the same layshaft (pretty much impossible).

 

That I have never heard of a DSG gearbox engaging both layshafts at once and grenading (including the millions of miles of testing that Ricardo did) shows that the logic controllers do not have human like characteristics of panicking and being stressed interfering with their decision making.

 

If you want to better understand the DSG gearbox I recommend that you download the relevant VAG self study guide, something I will do myself when I once again have access to a printer, I would like more detailed knowledge.

Edited 6 March, 2023 by J.R.

[numskull]

On 05/03/2023 at 12:26, J.R. said:

Vehicles have not generally used chain drive transmissions since the days of Frazer Nash.

Hmmmm. I’m guessing you’ve taken the word  “crashing” literally; I just meant it as a description. Yes, I’m aware of the FN Chain Gearbox. 

 

14 hours ago, J.R. said:

To avoid me reading through 4 pages of a thread only to perhaps find that it makes no mention of DSG gearboxes breaking due to downshifts from 2nd to 1st gear can you quote the relevant text please?

Well, although we’re mere mortals oh great one, expecting us to do that for you, is a bit of a stretch. 🙄

From what I can tell, the gearbox on our 280 selects 1st at around 2 or 3 mph when slowing to a stop and moves upto 2nd as low as 8-10mph when crawling in traffic or accelerating normally (whatever that is of course). 

[MarkyG82]

3 hours ago, J.R. said:

 

 

If you want to better understand the DSG gearbox I recommend that you download the relevant VAG self study guide, something I will do myself when I once again have access to a printer, I would like more detailed knowledge.

 

Thanks I will (when I have time).  Having read back my use of the word "panic" was misused.  I was intended it to sound human.  It was intended as a description of the box changing from it's preselect of 3rd to 1st.  Also not talking about engaging both shafts at the same time.

 

I also work with dynamics and having done some work into combined environments can state that non-linear responses can occur.  If you understand that terminology (I'm guessing you do) then I think we are arguing about things we both know about, but neither knows everything.  Probably wise to leave it there and get back to the gearbox talk.

[J.R.]

5 hours ago, numskull said:

20 hours ago, J.R. said:

To avoid me reading through 4 pages of a thread only to perhaps find that it makes no mention of DSG gearboxes breaking due to downshifts from 2nd to 1st gear can you quote the relevant text please?

Well, although we’re mere mortals oh great one, expecting us to do that for you, is a bit of a stretch. 🙄

 

No need for the sarcasm, I was responding to the post from MArky that said "But will it select 1 or 3 if slowing in 2 with engine at 2k revs as per this post breaking gearboxes?"

 

"This post" was not quoted and I could not see any post about gearboxes breaking from a downshift to 1st gear, so I was hoping he could tell me what (or where) it was so I could understand the question he asked me, I was not asking or expecting anyone else to do so.

[Ootohere]

They do not 'break', what happens very often with DQ200's is that they require Clutch Packs, or selectors or MCU's or actually new boxes but that is just the weaknesses.

Going down to 1st manually is not the issue there.  If you do it a few times and the noise or behaviour isas it can be you tend not to do it again.

 

Thew DQ250's have been quite robust, and the DQ381,s are looking like maybe not being so and damn expensive to service and more so to repair. 

 

The thing is that you can drive them as you want and maybe those that own them might be more careful with them than those that lease cars and return them after a year or 3.

That is then the next owners that might have no expenses or lots to spend out in the future with them.

 

It is only 2 pedal car driving, it is as easy as driving a dodgem...

[MarkyG82]

So I tried it today (engine around 2k in 2nd) and the car speed was about 20mph. Change down and all I got was some added noise. Can only assume that, being the hybrid, the electric motor rev matched (to roughly 3.5k). I got no added braking or crunchy stuff. I now want to try it in a dinosaur car to see the difference but I don't know anyone with a dsg anymore as they've all changed brand or gone back to Manuel.

[Ootohere]

[Donweather]

4 hours ago, MarkyG82 said:

So I tried it today (engine around 2k in 2nd) and the car speed was about 20mph. Change down and all I got was some added noise. Can only assume that, being the hybrid, the electric motor rev matched (to roughly 3.5k). I got no added braking or crunchy stuff. I now want to try it in a dinosaur car to see the difference but I don't know anyone with a dsg anymore as they've all changed brand or gone back to Manuel.

Not sure how you get compression braking with an electric motor. 

[numskull]

9 hours ago, J.R. said:

 

No need for the sarcasm, I was responding to the post from MArky that said "But will it select 1 or 3 if slowing in 2 with engine at 2k revs as per this post breaking gearboxes?"

 

"This post" was not quoted and I could not see any post about gearboxes breaking from a downshift to 1st gear, so I was hoping he could tell me what (or where) it was so I could understand the question he asked me, I was not asking or expecting anyone else to do so.

Sorry J.R.; I understand your annoyance. Not confirmed of course, but perhaps MArky meant “thread” as opposed to “post”? 

[MarkyG82]

2 hours ago, numskull said:

Sorry J.R.; I understand your annoyance. Not confirmed of course, but perhaps MArky meant “thread” as opposed to “post”? 

 

Quoted it above. From the first post on page 3 of this very thread.

[Graham Butcher]

I'm just curious as to why anyone would want to change down from 2nd to 1st, even for engine braking. I find that there is enough braking effect in 2nd as the car slows down enough the DSG will automatically select 1st anyway, even in manual mode, the down shifts happen automatically to prevent the engine labouring.

[J.R.]

5 hours ago, MarkyG82 said:

 

Quoted it above. From the first post on page 3 of this very thread.

 

I see it now, but I see nothing about "breaking gearboxes".

[MarkyG82]

On 05/01/2023 at 08:14, Donweather said:

DSG replaced today. Picked car up from dealer and driving car home I downshifted from 2nd to first whilst going down a hill and guess what……..crunch went the gear box.

 

@J.R. from the first page. Crunch certainly sounds like something broken to me.  Whether from this gear change or not it cant be helping the situation.