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My T-Roc is a 1.5 TSI DSG and is just over 3 years old with about 12500 miles on the clock.

Although I've previously tried the different driving profiles in the past, I have almost exclusively used the Normal profile over the past 3 years, but with the spiraling cost of petrol, I decided to revisit the Eco profile again to see if I can improve my consumption figures. There have been lots of discussions (including comments by myself) in several topics on this forum about the operation and the pros and cons of the various profiles and about the well known and discussed problem with the car not remembering and resuming the previous Eco settings after switching off and then on again, so I don't want to go back over all of those discussions again.

I'm starting this new topic because for the past week or so when I've been focusing on consumption, I have noticed increasing occasions where I cannot get my car to go into either 2-cylinder mode or coasting. Having driven the car for 3 years, and a Golf 1.4 DSG with similar driving profiles for 5 years before that, like many other forum members I'm fully familiar with when and how to engage 2-cylinder mode and coasting, and how they should operate. Both functions have worked fine until now.

When driving the same regular routes in near identical conditions (some around 3 miles and some up to 25 and 50 miles), some times I just cannot get the car to go into 2-cylinder mode (as indicated by the Eco symbol
Font Circle Symbol Electric blue Magenta
on the dash and 2-cylinder mode message in the MFD when displaying Consumption). I've tried switching between Normal, Eco and Individual driving profiles and it makes no difference. Then I find the following day, or sometimes even for a short time during a longer journey, it will suddenly start working again. I have the same problem with the coasting function, which I believe only acivates with the Eco profile although @twist has reported has car also coasts in Normal mode.

I also found when coming down a 1+ mile steepish hill with 2 long straights (the Haylie Brae for anyone who knows the Largs area), I had to keep my foot on the throttle to maintain speed and the off throttle deceleration was so bad that I even checked to make sure the brakes aren't binding. I would normally come down that hill with my foot fully off the throttle the whole way and manually shifting progressively down through the gears from 7 to 4 before applying the brakes.

My car was in the workshop yesterday for other problems and I asked them to also investigate these 2-cylinder and coasting issues. However, there were no errors logged for these so they basically say it's 'No fault found' and to get back to them if it recurs. That is a joke as it recurs constantly but it's not a hard fault and obviously is not producing log entries. Neither function activated once in my 25 mile journey home from the dealership last night !

I have asked the dealer to arrange a time when I can take a technician on a test drive to demonstrate the issues and compare against another car with the same engine and features, but because of the intermittency, that may require several visits involving a 50 mile round trip.

In the meantime, I'd like to hear from any owners who have experienced the same or similar problems with 2-cylinder mode and/or coasting and if any have had it investigated and fixed. I suspect it is a valve or something sticking and preventing the engine achieving the required conditions for activation, as a failure of any of the sensors involved is supposed to be logged.
 
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Your frustrations echo my experience trying to get the dealership to confirm the kangaroo issue with my first one. I know how you feel and how angry it makes you.

I agree though: the most logical explanation is that it’s a valve stuck or perhaps a sensor that’s showing an incorrect value but not flagging any errors. God knows how you’ll get them to look into that though unless you get a technician who actually understands how these things work and won’t just tell you it’s “working as intended.”

Did they charge you a diagnostics fee due to not finding anything?
 

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Discussion Starter · #3 ·
Thanks for the encouragement @twist .

There were no charges for the courtesy car or for the work carried out. That includeded updating the Sat Nav software for my vanishing street/place names, map freezing and not zooming etc., although I can't see why the software should start causing me problems after 3 years of daily use but I guess they have to install that first before exploring any other possible causes - it's trial and error rather than a definitive fix and time will tell if they have fixed it but it had been working ok for the past 3 weeks with the old software.

The also found an error logged for engine misfiring as probable cause of the sudden engine juddering I suffered a few weeks ago. Cleared the error and ran diagnostic tests but no further fault showed up so no actual identification or repair of what caused the issue.

As for the 2-cylinder and coasting issues, it is still one day good and the next day bad. So I have an appointment for 10th August to go out on a test drive with a technician - sod's law says that will be one of the good days.

I'm not that bothered about coasting as I hadn't used that much at all, but it is probably the same fault affecting both functions. But the loss of 2-cylinder mode has reduced my mpg by about 10%. I could regularly drive 25 miles to Glasgow and get 50mpg and that fell to the low 40's last Sunday even though I was driving about 10mph less than usual.

Did you ever confirm if your car still does coasting in any of the modes besides Eco ?
 

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Thanks for the encouragement @twist .

There were no charges for the courtesy car or for the work carried out. That includeded updating the Sat Nav software for my vanishing street/place names, map freezing and not zooming etc., although I can't see why the software should start causing me problems after 3 years of daily use but I guess they have to install that first before exploring any other possible causes - it's trial and error rather than a definitive fix and time will tell if they have fixed it but it had been working ok for the past 3 weeks with the old software.

The also found an error logged for engine misfiring as probable cause of the sudden engine juddering I suffered a few weeks ago. Cleared the error and ran diagnostic tests but no further fault showed up so no actual identification or repair of what caused the issue.

As for the 2-cylinder and coasting issues, it is still one day good and the next day bad. So I have an appointment for 10th August to go out on a test drive with a technician - sod's law says that will be one of the good days.

I'm not that bothered about coasting as I hadn't used that much at all, but it is probably the same fault affecting both functions. But the loss of 2-cylinder mode has reduced my mpg by about 10%. I could regularly drive 25 miles to Glasgow and get 50mpg and that fell to the low 40's last Sunday even though I was driving about 10mph less than usual.

Did you ever confirm if your car still does coasting in any of the modes besides Eco ?
Wow, that’s a substantial drop without 2-cylinder mode. I can see why you’re wanting it resolved. Frustrating about the misfire mystery too.

Yes, I did confirm coasting mode in Individual mode, I just forgot to post about it. I changed to Individual mode and swapped Drive to “Normal”. The car coasted within a matter of seconds after beginning my journey (although much less often than in Eco. I then changed Drive to “Eco” (still using Individual mode) and coasting happened all the time, as with Eco mode. Purely for curiosity I also tried Drive set to “Sport” and noticed zero coasting.
 

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That included updating the Sat Nav software for my vanishing street/place names, map freezing and not zooming etc., although I can't see why the software should start causing me problems after 3 years of daily use but I guess they have to install that first before exploring any other possible causes - it's trial and error rather than a definitive fix and time will tell if they have fixed it but it had been working ok for the past 3 weeks with the old software.
Is there a change in your software version? You were running 0891 previously. Maybe just a reinstall?
As you say, why did it run spot on for 3 years🤔🤷‍♂️
 

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Discussion Starter · #6 ·
... Frustrating about the misfire mystery too ...
I wonder if there is any link between the misfire and the 2-cylinder issue, as the former only happened once but just a week or two before I noticed the missing Eco symbol.

... I changed to Individual mode and swapped Drive to “Normal”. The car coasted within a matter of seconds ...
... I then changed Drive to “Eco” (still using Individual mode) and coasting happened all the time ...
Why should our 2 cars be different ? Even on a good day when I have 2-cylinder and coasting working, the coasting only ever happens when using the pre-configured Eco mode and never in Individual mode no matter how I set it.

This is reminiscent of how the Kangaroo affected some cars but not others.
 

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Discussion Starter · #7 ·
Is there a change in your software version? You were running 0891 previously. Maybe just a reinstall?
As you say, why did it run spot on for 3 years🤔🤷‍♂️
Yes, the software version has changed from 0891 and is now 0879.

Strange about those numbers (in line with your previous posts), and when I recently asked if there were any software updates for my car they said everything was at the latest version. I wonder if they wrongly assumed 0891 was more recent than 0879.
 

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I don’t understand how you can have a coasting feature on VW as I understand it casting = free wheeling which is supposed to be illegal? Freewheeling????
 

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I don’t understand how you can have a coasting feature on VW as I understand it casting = free wheeling which is supposed to be illegal? Freewheeling????
I guess it is because it is part of the DSG software and has been approved on that basis. By the same token, if I set the DSG shifter to Neutral in order to coast (despite VW saying that can damage the gearbox), then that would be considered illegal. Likewise driving behind another vehicle using ACC set to close distance is allowed, even though tailgating is illegal in the UK ?

I think the difference is that the DSG software will immediately and automatically re-engage a gear if I apply braking or throttle and I think also steering movement. Also, in order to provide engine braking, I think if the car detects going downhill it comes out of coasting. But as I said above, I very very seldom ever use Eco mode and coasting.
 

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and I think also steering movement. Also, in order to provide engine braking, I think if the car detects going downhill it comes out of coasting
Not in my car. I can steer while coasting and also it will allow me to coast while descending any degree of gradient, including very, very steep ones. My car only exits coasting mode if I tap the brakes, accelerate or change gear manually.

Maybe it’s a plot twist and my car is the faulty one :LOL:
 

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I wonder if they wrongly assumed 0891 was more recent than 0879.
I can't see why they'd think 0891 was up to date as they'd have to look it up regardless 🤔
I'm not sure what all changed on my MIB2 but I'm nearly sure? I could originally factory reset individual settings on my car via the menu but I now only have the option to factory reset everything in one swoop 🤔

Will be interesting to see if you notice anything?
 

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Discussion Starter · #12 ·
Not in my car. I can steer while coasting and also it will allow me to coast while descending any degree of gradient, including very, very steep ones. My car only exits coasting mode if I tap the brakes, accelerate or change gear manually.

Maybe it’s a plot twist and my car is the faulty one :LOL:
Maybe that's why the Owner's Manual doesn't attempt to give any detailed description of how to activate and what to expect from the coasting and 2-cylinder mode functions - no two cars are the same 😂🤣
 

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Discussion Starter · #13 ·
I can't see why they'd think 0891 was up to date as they'd have to look it up regardless 🤔
I'm not sure what all changed on my MIB2 but I'm nearly sure? I could originally factory reset individual settings on my car via the menu but I now only have the option to factory reset everything in one swoop 🤔

Will be interesting to see if you notice anything?
TBH I haven't looked. I was perfectly happy with everything for 3 years till it broke so I'm more interested in whether or not this 'update' has fixed the issue, but it is one of those annoying intermittent problems and I previously went 3 or 4 weeks between episodes so it's too early to tell.
 
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I have a 1.5 DSG R line, and mine is left in sport mode and the gearbox in normal D... Never used to coast but it has now started... i used to have it in the Normal driving mode but noticed it very rarely used to go into 2 cylinder mode... However in the setup i have it in now, it uses 2 cylinder mode loads more and coasts... plus it hasnt affected my mpg at all...46 pootling about and 53 on a motorway run.
 

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Discussion Starter · #15 ·
Thanks for the info @curlytops ... this gets stanger and stranger.

An update to my opening post 2-cylinder and coasting problems

Over the past 2 weeks, my car has been back to 'normal' which for me means 2-cylinder mode operates frequently in Normal and Eco modes while coasting operates frequently in Eco mode but never in Normal mode. Because I cannot reproduce the original problem, I cancelled yesterday's appointment for a test drive with a technician. I have yet to try Individual mode again and I will also now try Sport mode to see if either of these produces coasting.

It seems that @curlytops and @twist are seeing different behaviour to me, and also to each other so the mystery deepens.
 
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I have a 1.5 DSG R line, and mine is left in sport mode and the gearbox in normal D... Never used to coast but it has now started... i used to have it in the Normal driving mode but noticed it very rarely used to go into 2 cylinder mode... However in the setup i have it in now, it uses 2 cylinder mode loads more and coasts... plus it hasnt affected my mpg at all...46 pootling about and 53 on a motorway run.
What model year is your car? @Impala has a MY19 and I have a MY20. If yours is neither then that explains why we are all seeing different behaviors (they tweak the ECU - and various other management components - between model years).
 
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Discussion Starter · #17 ·
I did a fresh test today with Individual mode, changing only Drive to Eco setting. The car did go in to 2-cylinder mode, but not so often or readily as when using the preset Normal or Eco modes, but it never coasted once !

Still to try Sport mode using @curlytops setting.
 

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Discussion Starter · #18 ·
I have a 1.5 DSG R line, and mine is left in sport mode and the gearbox in normal D... Never used to coast but it has now started... i used to have it in the Normal driving mode but noticed it very rarely used to go into 2 cylinder mode... However in the setup i have it in now, it uses 2 cylinder mode loads more and coasts... plus it hasnt affected my mpg at all...46 pootling about and 53 on a motorway run.
@curlytops , do you deselect then reselect Sport mode every time you start the car? There are doubts about what engine and gearbox setting is actually used vs what is displayed if you don't.
 
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The coasting mode has to be activated every time you get into the car.
 

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The coasting mode has to be activated every time you get into the car.
What do you mean? There’s no specific option to turn on or off coasting mode.
 
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