Extreme engine braking DSG ??

[mikkelvitus]

Hello,

 

I have purchased a used car.

 

A Skoda superb 2.0 tdi CR 140 hp DSG MY 2014, with start stop and recuperation of energy.

 

When i drive to a red light, and just use the brakes very easy, i find the engine braking very agressive, to the point it is irritating me. 

 

I like the engine braking when going down hill, and it keeps upshifting as long i hold the brake, but in normal easy stop and go traffic it is way to aggressive.

 

Is there any solution to this ? Is it the recuperation that demands this aggressive engine braking ? Can it be disabled via vcds ?

 

Other solutions ?

 

BR
Mikkel

[3T51704x4]

Sorry, I can't comment as I don't own a DSG so would have no idea what is excessive. I sometimes find my brakes, in general, are very sharp, I think they have some adaption adjustment in 03, not sure if any adjustment possible for the DSG in 02 as not had to bother with it. I take it you have it in D and not S or Tip?

May just have to wait until someone with a later type (14 plate) DSG comments.

[chimaera]

The engine braking effect can be quite strong during downshifts under braking. It's something you adapt to pretty quickly.

[mikkelvitus]

Thanks but does anyone know if it can be disabled ?

 

I think the strong enginebraking occurs because of the recuperation system - charging via the alternator, as prv. cars with dsg without recuperation does not have this extreme engine braking. Can the system be disabled via vcds ?

[chimaera]

1 hour ago, mikkelvitus said:

Thanks but does anyone know if it can be disabled ?

 

I think the strong enginebraking occurs because of the recuperation system - charging via the alternator, as prv. cars with dsg without recuperation does not have this extreme engine braking. Can the system be disabled via vcds ?

I don't know what you mean by recuperation. The alternator is always in use. There is no regenerative braking system on these cars either.

The sudden increase in engine braking during these downshifts results from the DSG re-engaging the clutch quickly: you would get the same effect on a manual car if you took your foot off the clutch pedal quickly after changing down a gear. There may be some tuning in the DSG ECU that changes downshift behaviour if the driver brakes harder than a certain level but that probably won't be exposed in VCDS.

I found I got used to it within a few days and learned to lift the brake pedal a little when I know a downshift is about to happen and it's just not a problem.

[mikkelvitus]

11 hours ago, chimaera said:

I don't know what you mean by recuperation. The alternator is always in use. There is no regenerative braking system on these cars either.

The sudden increase in engine braking during these downshifts results from the DSG re-engaging the clutch quickly: you would get the same effect on a manual car if you took your foot off the clutch pedal quickly after changing down a gear. There may be some tuning in the DSG ECU that changes downshift behaviour if the driver brakes harder than a certain level but that probably won't be exposed in VCDS.

I found I got used to it within a few days and learned to lift the brake pedal a little when I know a downshift is about to happen and it's just not a problem.

 

There is no regenerative braking on thee cars ??

Well the production document for my car, says something different! Pls. look at photo.

 

As well as the Battery regulator module installed in my car. See photo.

 

 

 

 

[chimaera]

2 hours ago, mikkelvitus said:

 

There is no regenerative braking on thee cars ??

Well the production document for my car, says something different! Pls. look at photo.

 

As well as the Battery regulator module installed in my car. See photo.

 

 

 

 

That's the battery management functionality for the Start/Stop system. Frequent starts put more demands on the battery so there's a whole bunch of extra stuff in there to monitor and manage battery condition so that you won't be left stranded at traffic lights.

[mikkelvitus]

2 hours ago, chimaera said:

That's the battery management functionality for the Start/Stop system. Frequent starts put more demands on the battery so there's a whole bunch of extra stuff in there to monitor and manage battery condition so that you won't be left stranded at traffic lights.

 

Eeehm... The first photo taken from production specification on exactly my car. It says, and i Quote "Stop Start system with regenerative braking".

The screenshot from battery managment says the same.

The last photo is from the 09 BCM module - which states that recuperation is active.

 

How can you then claim that there is not regenerative braking on my car ?

The recuperation function works to charge the batteri while engine braking.

 

It does'nt seem that you know about this functionality.

[mikkelvitus]

Please is there someone here, who actually knows about these systems, and not just guessing without knowledge ?

 

I would really like to remove that regenerative braking. At least i now get the start/stop system sortet - Im mounting a little bit og hardware, which will alter the function of the start/stop button, in a way so it will remember its state across ignition on/off's... Aah a blessing

[xman]

I am not an expert and have never looked at a Superb mk2 as I have the mk3.

 

But I have read on Briskoda that if you unplug the small connector on the battery current sensor which is part of the battery negative terminal, it loses the ability to track the battery state of charge, the car allegedly will then disable Start/stop and the regen/smart charging functions, and the alternator reverts to conventional old fashioned fixed voltage (14.3) charging.

 

Cannot confirm if this true however, but easy to try.

[mikkelvitus]

Thanks - i will try that!!

 

[silver1011]

Sorry, I can't help with whether or not it can be disabled, but regenerative braking has been around on some Skoda models for several years, at least since the MkIII Octavia was launched back in February 2013. For current VAG cars "Regenerative Braking" means that when the car is decelerating or braking the alternator load is increased to harvest some of the kinetic energy and charge up the battery. It is likely that this is the reason for the increased engine braking you are experiencing.

 

 

So, it's very possible the same technology is fitted to your 2014 facelift Superb.

 

 

 

[mikkelvitus]

Thank you Silver, its exactly what my superb is fitted with.

 

When braking the engine revs increases så that the alternator can charge and the engine helps braking the car.

 

But i want to get rid of this functionality, and hoped that someone knew how to turn it off in vcds. I have tried to disable the start stop system, but it must be managed somewhere else, because the system is still functioning, even when its disabled .

 

I had hoped someone could advise - it could be a matter of specifying another type of battery than AGM, or another parameter, that would stop this regenerative engine braking.

[silver1011]

It might be worth posting in the dedicated VCDS forum, this is where all the VCDS guru's hang-out 

 

https://www.briskoda.net/forums/forum/23-diagnostics-amp-vcds/

[mikkelvitus]

7 minutes ago, silver1011 said:

It might be worth posting in the dedicated VCDS forum, this is where all the VCDS guru's hang-out 

 

https://www.briskoda.net/forums/forum/23-diagnostics-amp-vcds/

 

Thank you very much, i will try that

[AlexVicol]

Regarding Start/Stop , for my 2014 FL 170 4x4 dsg the following works:

VCDS - 19 Gateway -> (Long) adaption -> channel 13 -> change code 002000 into 292029

[silver1011]

Is the stop/start feature connected to regenerative braking?

[AlexVicol]

No, I still have the regenerative braking with start/stop disabled.

I've posted a solution for the those who want to disable start/stop as mikkelvitus was trying to do.

[Breezy_Pete]

I have some doubts that it is the alternator that is causing the harsh engine braking. I just don't think the alternator can harvest kinetic energy fast enough to 'feel' like that, no matter what its electrical parameters are set to.

You could experiment if you are feeling brave though. The LIN connection is what controls the alternator. If that wire were disconnected, it would probably default to a constant voltage charging regime. You could see if the braking behaviour stayed the same or changed as you wish.  Expect warning lights. I think nothing should be damaged, as the system should be designed to survive loss of control signal.

[langers2k]

As above, I'd be surprised if an alternator would cause extreme engine braking.

 

Looking online, the biggest possible alternator is 180A so around 2-2.5KW at maximum load. Assuming it's about 50% efficient that's a absolute maximum of 5KW worth of engine braking which doesn't feel like much. Especially when a proper EV can get 60KW+. In the SSP documents I've come across, there isn't that much mentioned but it does seem it'll work like 'micro-hybrid'. Basically the car will reduce alternator load when accelerating to give you more power and then increase alternator load when braking to recuperate the energy.

 

 

It's probably worth getting the battery checked properly (not just voltage) as I expect a failing battery could cause the system to try and charge it more? I assume that disabling stop/start makes no difference?

 

 

 

If you really want to try and disable it, I'd suggest you make a full autoscan of your car and take adaption maps for every module. This will give you the best chance of recovering the original coding if/when it doesn't work. You can then try changing the bits you've pointed out and see which (if any) modules throw error codes and work through the car until there are no faults left. Be warned, some modules might have different software installed for stop/start and recuperation support so they may refuse coding changes or have permanent fault codes if you change the coding.

 

Assuming your VCDS is genuine, it might be worth asking Rosstech for support as what you're trying to do certainly doesn't fit in to the normal tweaks/retrofits most users will be familiar with.

 

[chimaera]

10 hours ago, mikkelvitus said:

When braking the engine revs increases så that the alternator can charge and the engine helps braking the car.

That sounds exactly like a gearchange. Have you looked at the gear position indicator while this is going on?

[mikkelvitus]

2 hours ago, AlexVicol said:

Regarding Start/Stop , for my 2014 FL 170 4x4 dsg the following works:

VCDS - 19 Gateway -> (Long) adaption -> channel 13 -> change code 002000 into 292029

Ok thanks.

 

I know that the regenerative braking is working independant of the start/stop. I will try that coding - does it make the light in the start/stop button to be permanent on?

 

And to all others. Well i didn't mean that the alternator is doing all the braking force, but the dsg downshifts very much, approaching a red light, to make the alternator spin faster i assume, and to provide additional braking force via the engine. Maybee its just something to get used to, but i would like to have the dsg just not interveen in my braking when im comming to a stop. On the other hand i like the intellligent downshifts when braking down a steep hill.

[mikkelvitus]

12 minutes ago, chimaera said:

That sounds exactly like a gearchange. Have you looked at the gear position indicator while this is going on?

Yes but it is just gearchanges. Engine braking just like you would do in a manual car.

[AlexVicol]

1 minute ago, mikkelvitus said:

I know that the regenerative braking is working independant of the start/stop. I will try that coding - does it make the light in the start/stop button to be permanent on?

No, it'll stay off .

This codding will just make one condition not be fulfilled and start/stop will be disabled.

[langers2k]

22 minutes ago, mikkelvitus said:

And to all others. Well i didn't mean that the alternator is doing all the braking force, but the dsg downshifts very much, approaching a red light, to make the alternator spin faster i assume, and to provide additional braking force via the engine. Maybee its just something to get used to, but i would like to have the dsg just not interveen in my braking when im comming to a stop. On the other hand i like the intellligent downshifts when braking down a steep hill.

 

To be honest, you shouldn't get that much engine braking from a TDi as there isn't a butterfly on the inlet that can be closed like a petrol engine.

 

What sort of RPM is the engine getting down to before it's downshifting?

 

There's also a chance a previous owner may have had the DSG remapped which could cause more aggressive shifts. Have you got a full autoscan?