[Barnaclebob]

My Golf 1.5 TSI EVO was in the dealers yesterday to investigate exactly the same fault. They found nothing and no record in the history.
I found that if I drive with the lights set to off instead of auto the message did not occur. Of all the times it did occur my lights were on; no wipers, air-con etc. Strangely I have driven for just under five hours today with lights on auto, so they were switching on and off variously as necessary, and no error message! Prior to the garage investigation it never failed to appear if the headlights were on, usually between 20 - 60 minutes into a journey. Perhaps their investigations inadvertently tweaked something to correct it?
At least I got a free wash and vacuum out of the visit.

Or they're not being honest with you...?

 

[Aaaargh]

If they had found a fault they could bill VW for repairing it under warranty?

 

[retiredbri]

Hi, I can reproduce the fault only if the car is coasting. Get yourself on a longish hill and when the car is coasting (the engine will stop), turn the lights on and the blower on full and the wipers and maybe the air con and then apply the brakes to force the car out of coast (or press the accelerator). With me, the engine that had stopped tried to start, failed at 500rpm then started. Theis caused the fail message to appear.
Regards retiredbri

 

[Impala]

Hi, I can reproduce the fault only if the car is coasting. Get yourself on a longish hill and when the car is coasting (the engine will stop), turn the lights on and the blower on full and the wipers and maybe the air con and then apply the brakes to force the car out of coast (or press the accelerator). With me, the engine that had stopped tried to start, failed at 500rpm then started. Theis caused the fail message to appear.
Regards retiredbri

A couple of things Retiredbri.

I previously had a 2014 Golf Mk7 DSG and now have a T-Roc DSG. On both of these cars, coasting was/is enabled by selecting Economy (ECO) driving mode and when activated by taking my foot of the throttle, the enginge revs dropped to idling speed (~ 600rpm).

I found two relevant statements in the T-Roc manual.

The first is a general description of Coasting with DSG ...

The second, even more relevant, is about troubleshooting the Start/Stop system ...

What I believe is happening is that Coasting initially disengages the engine and drops the revs to idle speed, at which point the Start/Stop system kicks in and stops the engine just as it would do if you pulled up at traffic lights for example.

Now, you switch on various 'consumers' as VW calls them, such as turn the lights on and the blower on full and the wipers and maybe the air con. Next, you wish to end coasting by applying the brakes (you could also apply some throttle), so the engine starts but at the same time the Start/Stop system has sensed the additional load and normally by itself this also would start the engine. So the two systems - Coasting and Start/Stop - are both trying to start the engine at the same time but for different reasons and this generates the error message.

The troubleshooting statements above must surely mean the VW know this Vehicle Power System error can occur under these conditions (ie coasting with Start/Stop enabled), and they even say take the car to the workshop.

I must admit that I don't use ECO driving mode very often, either now with the T-Roc or previously with the Golf, but it does sound like the T-Roc and new Golf engine may stop when coasting, and this may be different from the older Golf Mk7. This is another example of how agressive the current Start/Stop system is, stopping the engine for any excuse and it is known this happens while 'coasting' to a stop at traffic lights etc.

Clearly something is not right if the engine isn't restarting and/or you get the error message, so it will be interesting to hear what the workshop finds.

 

[retiredbri]

The most terrifying thing happened today. I was Not in Eco mode but in D mode. I approached a 1 in 5 hill to go down. The engine changes down for engine braking but when I apply he brakes to slow the car down more, it resumes engine braking and then resumes Coast mode. Apply brakes again and the cycle repeats. There is no way I can keep it in engine braking mode. goes into Coast mode. Apply brakes again and I have engine braking back. Apply brakes again and back into Coast mode!. THe car is now in runaway mode. The only thing I could do is shift into Manual. Engine braking now under my control. Stop at bottom (half mile long hill). Fierce heat from the brakes and change of trousers for me.
VW in trying to save every drop of fuel have made the car undriveable. I've told the dealer I will be in on Saturday to reject a 13 day old car.
Regards retiredbri.

 

[T Roo]

The most terrifying thing happened today. I was Not in Eco mode but in D mode. I approached a 1 in 5 hill to go down. The engine changes down for engine braking but when I apply he brakes to slow the car down more, it resumes engine braking and then resumes Coast mode. Apply brakes again and the cycle repeats. There is no way I can keep it in engine braking mode. goes into Coast mode. Apply brakes again and I have engine braking back. Apply brakes again and back into Coast mode!. THe car is now in runaway mode. The only thing I could do is shift into Manual. Engine braking now under my control. Stop at bottom (half mile long hill). Fierce heat from the brakes and change of trousers for me.
VW in trying to save every drop of fuel have made the car undriveable. I've told the dealer I will be in on Saturday to reject a 13 day old car.
Regards retiredbri.

Awful experience; glad you're ok retiredbri.

 

[Impala]

The most terrifying thing happened today. I was Not in Eco mode but in D mode. I approached a 1 in 5 hill to go down. The engine changes down for engine braking but when I apply he brakes to slow the car down more, it resumes engine braking and then resumes Coast mode. Apply brakes again and the cycle repeats. There is no way I can keep it in engine braking mode. goes into Coast mode. Apply brakes again and I have engine braking back. Apply brakes again and back into Coast mode!. THe car is now in runaway mode. The only thing I could do is shift into Manual. Engine braking now under my control. Stop at bottom (half mile long hill). Fierce heat from the brakes and change of trousers for me.
VW in trying to save every drop of fuel have made the car undriveable. I've told the dealer I will be in on Saturday to reject a 13 day old car.
Regards retiredbri.

Hi retiredbri, sorry to hear of your change of trousers episode.

I've never had any significant engine braking initiated by the car itself either in my previous Golf DSG or in my T-Roc.

When descending a steep hill on a fairly frequent route, I always use the paddle shift to gradually go down through the gears in conjunction with intermittently applying the foot brake. This takes me from about 55 mph in 7th gear at the top of the hill, down to around 25 mph in 3rd gear for two sharp bends near the bottom.

That is in line with the advice in owner's manual ...

Why do you think the car will change down by itself ?

Clearly your driving style and use of the DSG is different from mine, and I'd also suggest it is not what is recommended by VW for driving down hills.

I can't explain why your car is going into Coast mode under these conditions. Do you see a message in the trip computer/ centre area of the Active Info Display which says 'Coasting', or is there some other indication that the car is going in and out of Coast mode. If it is really coasting in this scenario, then it definitely sounds like there is a fault, which should be fixable.

As this is not a normal characteristic of the DSG, I don't understand your rush to rejection and you will have to allow the workshop the opportunity to inspect/test the car anyway.

 

[retiredbri]

Hi all and thanks for the comments.
History: Before the 2019 Golf we had a 2014 Skoda Octavia 1.4 TSI with DSG. In ECO mode (and ONLY in ECO Mode) could the engine enter Coast Mode. Even then, the engine only went to idle and would flip back into drive (and Engine Braking) the instant one of the two DSG clutches released.
If I was in D mode and started going downhill AND took my foot off the accelerator AND the speed built up rapidly THEN the DSG changed to a lower gear and the revs went up. If I applied the brakes, the DSG would change down again to slow the car even more. I have never had to use the manual gear mode.

Now. The Golf 2019 handbook for the 1.5tsi EVO 130 with DSG says (page 132): "When the ECO Coasting Function is active, the engine is not only disengaged but also switched off".
This handbook was not available before we bought the car. Also, it doesn't say that the engine has to restart and the clutches released before you had "drive and engine braking".
This is the FIRST MAJOR difference
It also a worrying feature. I, like many others switched "Stop-Start" off to avoid wear and tear on the Starter motor.

Now, coming back to Coast Mode. With the 2019 Golf with the 1.5 TSI EVO 130ps with DSG, the Coast Function is active in both ECO and "D" Mode. This is the SECOND MAJOR difference!
I didn't know, the Sales Manager didn't know. Even more, he didn't know that the engine is switched off.
My wife has NEVER used Cruise Control because she always wants to be firmly in control. She used to happily drive 180 miles using the M5, M42, M40. M25 and M11 on her own to see her Mother. But now, with "Coast Mode" just switching in and out without warning, she is forced to "not be in control". So much so, she is nauseous and frightened (we are both in our 70's) and now REFUSES to drive the Golf.
I suspect it is a design feature in all Golfs rather than a fault in our car hence plan to return the car as "not fit for purpose".
Now, dealing with the instance on the hill. We started and were under control with engine braking. We needed to slow down more so applied more pressure on the brakes. It was then that we released the pressure momentarily that the car entered "Coast Mode" twice without warning. Our speed increased rapidly put me into panic mode and cause my wife to SCREAM!!!
It's easy to say "but the handbook says ". We were in the situation because of a design fault with the "Coast Mode" and going too fast. I could only engage the gears manually because there was no drive. (See my earlier comment about the Skoda engaging lower gears for me). We hadn't a clue as to how soon the brakes would work before they faded.

In answer to Impala's question: The display says "Coasting". The revs are "zero", the selected gear says "D" (without a number) and when going downhill, the speed is increasing. If I apply the brakes again, it sometimes comes out of Coasting for a second, the engine revs go up. AND then the revs go back to zero and message "coasting" comes up again. Once, entering a small town, it did it six times on the trot!

Finally: The Coast Function on the on the 2019 engines (and certainly the 130PS versions) utilises a separate Lithium Ion battery located under the passenger seat. This battery is, I believe, used to keep the brake servo working and to provide power to the power steering pump as well as powering the fault monitoring circuits.
At all times, I had Stop-Start turned off.
When the fault occurs, it is because this main battery cannot provide enough power to restart the stationary "Coast Mode" engine. Remember, the engine alternator is providing zero power.
Regards Retiredbri

 

[Aaaargh]

I tend to use the adaptive cruise control as often as I can as it will pull you up to a complete stop in traffic (scary the first couple of tries), but the main reason is than much of my driving to and from London is on motorways and A roads, many with long steep hills. With ACC on the car chooses when to apply brakes or use engine braking and you can see it often jumping between the two. Unless it's unbearably hot weather and I want the AC on constantly I never turn off stop/start. However, I have noticed that even with stop/start off it does not prevent the engine switching off whilst coasting, only when you come to a complete stop! The whole point of this technology is to reduce emissions where possible. Engine braking certainly does not help on that count. I'd rather spend the money on new brake pads more often, than repairing a clutch or the engine.

As an update to my original post I've done about 1000+ miles in all weathers, except snow, with my lights on auto and often air conditioning since the dealer had the car in last Thursday and "found nothing" and I haven't had a repeat of the vehicle power system error message once. They must have done something, even if it was suppressing the message somehow?

 

[Sbw60]

Sorry to 'hack' The TRoc forum - but just got new 1.5 golf 130PS DSG last week- twice yesterday the 'vehicle power system error' - contact workshop
They didn't know anything about this error !!
Have Volkswagen DEFINITELY got a fix for this ? - car only 8 days old & 250 miles !!

 

[Aaaargh]

Hi Sbw60
I don't know if there is a fix, but I haven't had this happen for over a week since the garage had it in. They said that they could not find the problem and had checked for software updates. They probably don't know what they done but it worked.
I found that having the headlights set to off rather than auto prevented it from happening, although the running lights are always on there will be times you need your headlights however.
I could give you the dealer's details but they will probably say that they don't know what it is (officially or unofficially).

 

[Sbw60]

Thanks-I'm taking it to dealer on Monday am b-seems to happen when car warmed up and on 'overrun' /coasting-but wouldn't want this to be a continuing problem 😳😳
Could it be rejected if this continues?
My wife has a pacemaker-does anyone know if the lithium ion battery below passenger seat would present issues to her when sitting in passenger side ?

 

[retiredbri]

Sorry to 'hack' The TRoc forum - but just got new 1.5 golf 130PS DSG last week- twice yesterday the 'vehicle power system error' - contact workshop
They didn't know anything about this error !!
Have Volkswagen DEFINITELY got a fix for this ? - car only 8 days old & 250 miles !!

In my case the workshops saw the fault in the computer fault log, They sent the details to VW and they have a mod kit. Mine should be fitted on 14th August.
Hope this helps
regards retiredbri

 

[Aaaargh]

Well that didn't last long!
11 days after the garage said that they could not find any problem the error message came back on Monday morning about 15 mins after leaving home. As usual it cleared after turning ignition off and there were no apparent problems. On Tuesday I did about 200 miles and no error message. Today (Wednesday) it happened four times!! When I started out I had no fan on or any other extra potential power hungry sources. The message came on within 5 mins.
The weather has been progressively bad all day, so at various points I had AC, heated mirrors etc on but it happened with AC on at one point, with it off also and I even unplugged my hardwired dash cam and it happened then too. The only constant since Monday was that the dipped beam was set to auto and today the rain caused them to turn on for extended periods. So I go back to my original supposition that it has something to do with the lights, but I don't know why it took 11 days to re-appear!
Has anyone else had any joy yet?

 

[retiredbri]

Sorry to 'hack' The TRoc forum - but just got new 1.5 golf 130PS DSG last week- twice yesterday the 'vehicle power system error' - contact workshop
They didn't know anything about this error !!
Have Volkswagen DEFINITELY got a fix for this ? - car only 8 days old & 250 miles !!

After the "Steep hill Coast Problem" that I described earlier, my wife was terrified of the Golf and would not drive it. We couldn't wait while VW prevaricated over a possible "Coast Mode" fix so we part exchanged it for an older Skoda that was based on 1.4 TSI engine. Sounds drastic but we needed a solution. She drove the Skoda home through every kind of weather in heavy traffic and was so relieved that she was back in control.

The net outcome was that we didn't go back to the VW dealer to have the 'vehicle power system error - contact workshop" fix that VW had ready. The Skoda dealer also has a VW dealership as well. They were not worried about the error and were confident that they could apply the VW "fix".
By the way, the error came up twice on our way to the Skoda dealer. With the very heavy rain and dark clouds it was just the right recipe (lights, heater, blower, aircon) to make it happen.

To all of you out there who have the problem PLEASE see my posts and findings. The error is caused when there is not enough power from the secondary battery to restart the engine REGARDLESS of what causes the excess power demand. It is not just one thing but a mixture - lights, wipers, blower, air con.
If you concentrate on ONE thing, I don't think you will be able to replicate the fault to order. The first time I had it, the dealer used used the scenario I described and they had the proposed fix from VW within two hours.

Thank you all for allowing me to 'hack' the TRoc forum. I'll leave now and hope that you get it fixed.
Regards Retiredbri.

 

[Clubchamp98]

Hi, I can reproduce the fault only if the car is coasting. Get yourself on a longish hill and when the car is coasting (the engine will stop), turn the lights on and the blower on full and the wipers and maybe the air con and then apply the brakes to force the car out of coast (or press the accelerator). With me, the engine that had stopped tried to start, failed at 500rpm then started. Theis caused the fail message to appear.
Regards retiredbri

A couple of things Retiredbri.

I previously had a 2014 Golf Mk7 DSG and now have a T-Roc DSG. On both of these cars, coasting was/is enabled by selecting Economy (ECO) driving mode and when activated by taking my foot of the throttle, the enginge revs dropped to idling speed (~ 600rpm).

I found two relevant statements in the T-Roc manual.

The first is a general description of Coasting with DSG ...

Coasting with DSG.jpg

The second, even more relevant, is about troubleshooting the Start/Stop system ...

Troubleshooting - Vehicle Power System.jpg

What I believe is happening is that Coasting initially disengages the engine and drops the revs to idle speed, at which point the Start/Stop system kicks in and stops the engine just as it would do if you pulled up at traffic lights for example.

Now, you switch on various 'consumers' as VW calls them, such as turn the lights on and the blower on full and the wipers and maybe the air con. Next, you wish to end coasting by applying the brakes (you could also apply some throttle), so the engine starts but at the same time the Start/Stop system has sensed the additional load and normally by itself this also would start the engine. So the two systems - Coasting and Start/Stop - are both trying to start the engine at the same time but for different reasons and this generates the error message.

The troubleshooting statements above must surely mean the VW know this Vehicle Power System error can occur under these conditions (ie coasting with Start/Stop enabled), and they even say take the car to the workshop.

I must admit that I don't use ECO driving mode very often, either now with the T-Roc or previously with the Golf, but it does sound like the T-Roc and new Golf engine may stop when coasting, and this may be different from the older Golf Mk7. This is another example of how agressive the current Start/Stop system is, stopping the engine for any excuse and it is known this happens while 'coasting' to a stop at traffic lights etc.

Clearly something is not right if the engine isn't restarting and/or you get the error message, so it will be interesting to hear what the workshop finds.

Hi I have an issue with the start stop as we have discussed before.
Just reading this .
My T-Roc in eco going downhill dosnt shut the engine down but goes into eco mode only using two pistons .
The revs stay the same .
Is this normal or only on the 1.5 DSG.

 

[Impala]

Hi, I can reproduce the fault only if the car is coasting. Get yourself on a longish hill and when the car is coasting (the engine will stop), turn the lights on and the blower on full and the wipers and maybe the air con and then apply the brakes to force the car out of coast (or press the accelerator). With me, the engine that had stopped tried to start, failed at 500rpm then started. Theis caused the fail message to appear.
Regards retiredbri

A couple of things Retiredbri.

I previously had a 2014 Golf Mk7 DSG and now have a T-Roc DSG. On both of these cars, coasting was/is enabled by selecting Economy (ECO) driving mode and when activated by taking my foot of the throttle, the enginge revs dropped to idling speed (~ 600rpm).

I found two relevant statements in the T-Roc manual.

The first is a general description of Coasting with DSG ...

Coasting with DSG.jpg

The second, even more relevant, is about troubleshooting the Start/Stop system ...

Troubleshooting - Vehicle Power System.jpg

What I believe is happening is that Coasting initially disengages the engine and drops the revs to idle speed, at which point the Start/Stop system kicks in and stops the engine just as it would do if you pulled up at traffic lights for example.

Now, you switch on various 'consumers' as VW calls them, such as turn the lights on and the blower on full and the wipers and maybe the air con. Next, you wish to end coasting by applying the brakes (you could also apply some throttle), so the engine starts but at the same time the Start/Stop system has sensed the additional load and normally by itself this also would start the engine. So the two systems - Coasting and Start/Stop - are both trying to start the engine at the same time but for different reasons and this generates the error message.

The troubleshooting statements above must surely mean the VW know this Vehicle Power System error can occur under these conditions (ie coasting with Start/Stop enabled), and they even say take the car to the workshop.

I must admit that I don't use ECO driving mode very often, either now with the T-Roc or previously with the Golf, but it does sound like the T-Roc and new Golf engine may stop when coasting, and this may be different from the older Golf Mk7. This is another example of how agressive the current Start/Stop system is, stopping the engine for any excuse and it is known this happens while 'coasting' to a stop at traffic lights etc.

Clearly something is not right if the engine isn't restarting and/or you get the error message, so it will be interesting to hear what the workshop finds.

Hi I have an issue with the start stop as we have discussed before.
Just reading this .
My T-Roc in eco going downhill dosnt shut the engine down but goes into eco mode only using two pistons .
The revs stay the same .
Is this normal or only on the 1.5 DSG.

That's how my DSG works. Can't comment on manual boxes, and it could be influenced by driver gear selection/changes.

 

[Impala]

Sorry to 'hack' The TRoc forum - but just got new 1.5 golf 130PS DSG last week- twice yesterday the 'vehicle power system error' - contact workshop
They didn't know anything about this error !!
Have Volkswagen DEFINITELY got a fix for this ? - car only 8 days old & 250 miles !!

After the "Steep hill Coast Problem" that I described earlier, my wife was terrified of the Golf and would not drive it. We couldn't wait while VW prevaricated over a possible "Coast Mode" fix so we part exchanged it for an older Skoda that was based on 1.4 TSI engine. Sounds drastic but we needed a solution. She drove the Skoda home through every kind of weather in heavy traffic and was so relieved that she was back in control.

The net outcome was that we didn't go back to the VW dealer to have the 'vehicle power system error - contact workshop" fix that VW had ready. The Skoda dealer also has a VW dealership as well. They were not worried about the error and were confident that they could apply the VW "fix".
By the way, the error came up twice on our way to the Skoda dealer. With the very heavy rain and dark clouds it was just the right recipe (lights, heater, blower, aircon) to make it happen.

To all of you out there who have the problem PLEASE see my posts and findings. The error is caused when there is not enough power from the secondary battery to restart the engine REGARDLESS of what causes the excess power demand. It is not just one thing but a mixture - lights, wipers, blower, air con.
If you concentrate on ONE thing, I don't think you will be able to replicate the fault to order. The first time I had it, the dealer used used the scenario I described and they had the proposed fix from VW within two hours.

Thank you all for allowing me to 'hack' the TRoc forum. I'll leave now and hope that you get it fixed.
Regards Retiredbri.

Hi Retiredbri,

I'm intrigued by your references to a secondary battery ...

The error is caused when there is not enough power from the secondary battery to restart the engine

I know you have said this battery is under the front passenger seat, so I've just been out to my T-Roc and had a look under the seats and there is no such battery on my car, but then I also don't have this engine switch off issue so the T-Roc may be different.

Are you sure this is for starting the engine, or do you have some extras on the car that it may be part of ? As far as I know, the Start/Stop system just uses the main (only) battery for restarting and I don't understand why a secondary battery would be used or needed.

I know your car is/was a new Golf and I think you said the engine switching off when coasting came as a shock, so I guess there is no mention or description of this in any of the VW web pages or publications. What about the Owner's Manual ... anything at all in there ?

Are there any posts from other owners on other forums or anything in press reviews of the car ?

 

[Aaaargh]

My 1.5 TSI DSG Golf slips into "2-cylinder mode" at every opportunity and 'eco' is displayed at the bottom of the rev counter whatever performance environment you're in (Drive, ECO, or Sport). Eco also displays when it is in coasting mode having turned the engine off. Turning off start/stop using the button by the gear selector only prevents the engine turning off when coming to a complete stop. It does not prevent it stopping whilst moving/coasting.

Update: no error warning at all today (6:00 - 15:00 driving south coast to London to various appointments in London and returning home). Probably because it hardly rained and the auto dipped beam only came on a few minutes at a time.

 

[Vwvwvwvw99]

Hi I haven't been on here for a few weeks and now noticed lots of replies to my initial comments so though I would bring up to speed on my situation.

1.5 golf 130 Dsg golf and been getting these error messages as well. Only 2 months old now but been happening since new a few times.

First time in garage they said "battery needed coding" which I assume was a software update. Second time said made "adaption" to aux battery but not sure what that means - This was after they spoke to VW technical.

Since then it's calmed down and only come on once more over a few weeks period.

Garage just looked at it again and said that vw technical have said that most cases the software reset and adaptions has fixed the problem. For others they are also now looking at replacing the li ion battery as next step. Although I don't think that will help I will let them do it in the hope this resolves it.

I also found out that it seems to happen more in auto mode when it rains. I thought it was a coincidence but glad others have mentioned this. I did mention this to the dealer.

Also thinking if doesn't resolve will look at rejecting car. I do wonder if as the bad weather starts to happen we will be getting more reports of this occurring.

I've just clicked notify of replies to this thread to keep updated and remember to keep you all updated.