Predictive Adaptive Cruise keeps dropping to 60 on A roads

[Antimus]

I've had pacc retrofitted to my 2017 FL vrs and just started really using it on long drives, on motorways it's great but on dual carriageway A roads it keeps "detecting" 60MPH then a few seconds later going back to 70, which obviously screws with the cruise control in a big way. I've had it on the A1, A43 and another one I went along today.

 

Is this normal or do I need to get some recoding done?

 

I updated the maps early this year belt the retrofit .

[varooom]

Are you near any parallel roads when this occurs, as could be flipping you between the 2 roads?

[KenONeill]

3 minutes ago, Antimus said:

I've had pacc retrofitted to my 2017 FL vrs and just started really using it on long drives, on motorways it's great but on dual carriageway A roads it keeps "detecting" 60MPH then a few seconds later going back to 70, which obviously screws with the cruise control in a big way. I've had it on the A1, A43 and another one I went along today.

 

Is this normal or do I need to get some recoding done?

 

I updated the maps early this year belt the retrofit .

Given that PACC sets speeds based on what road it thinks it is on, this is a surprise why?

[Antimus]

6 minutes ago, varooom said:

Are you near any parallel roads when this occurs, as could be flipping you between the 2 roads?

I thought that might be it but no, happens even when no other roads are around

[varooom]

1 minute ago, Antimus said:

I thought that might be it but no, happens even when no other roads are around

Probably naff maps, not programmed right and get's it wrong.

[Antimus]

4 minutes ago, KenONeill said:

Given that PACC sets speeds based on what road it thinks it is on, this is a surprise why?

Not sure you understand the problem, the speed limit of the road doesn't change from 70 to 60 to 70 within the space of 200 metres multiple times along the A1. There are no speed signs saying 60 and the map data should show it as a 70 road most of the way down.

 

So yes, it's a surprise that the car does it, why shouldn't it be?

Just now, varooom said:

Probably naff maps, not programmed right and get's it wrong.

I'll try updating maps again when I get home

[KenONeill]

20 minutes ago, Antimus said:

speed limit of the road doesn't change from 70 to 60 to 70 within the space of 200 metres multiple times along the A1

It doesn't have to; you just need a GPS error that leads to it thinking that you're on a parallel single carriageway road.

[Antimus]

Just now, KenONeill said:

It doesn't have to; you just need a GPS error that leads to it thinking that you're on a parallel single carriageway road.

No parallel roads or roads even close by some of the times it happened.

 

Do you have pacc and this happens to you as well then?

[KenONeill]

4 hours ago, Antimus said:

Do you have pacc

I repeat " you just need a GPS error". Got it now?

[Antimus]

But the navigation doesn't move my location, there are no roads nearby.

 

It's not like I'm jumping all over, and it doesn't happen on motorways.

 

Look I think you're not really helping here and if you don't either have pacc and have the same problem, or have it and don't, then just move on and let someone else reply.

 

I'm honestly not sure why the attitude to be honest, it's been since your first comment.

[nige8021]

30 minutes ago, Antimus said:

 

Look I think you're not really helping here and if you don't either have pacc and have the same problem, or have it and don't, then just move on and let someone else reply.

 

I'm honestly not sure why the attitude to be honest, it's been since your first comment.

 

I think you're the one with an attitude, @KenONeill a forum user who has years of experience has given you a perfectly plausible cause, you might not see the map display jump but that doesn't mean the GPS data hasn't  

[Kenai]

I'd have pointed the finger of suspicion at 'retrofitted' before GPS errors personally. 

 

I'd be inclined to try and find someone who could perhaps double check the coding associated with the retrofit has been done correctly. 

[john999boy]

I presume pacc gets overridden by camera detected speed limits? Does the same thing happen in exactly the same places?

 

[KenONeill]

1 hour ago, Antimus said:

I think you're not really helping here

OK, if you don't want help from a software engineer who has over 194 comments for each one you've made, and who works with GPS systems, who do you want hold from?

[Antimus]

8 hours ago, john999boy said:

I presume pacc gets overridden by camera detected speed limits? Does the same thing happen in exactly the same places?

 

No speed limit signs even close to where it's happening. It's like the map data just switches from 70 to 60 to 70, but that must mean it happens to everyone with my map data and I can't find anyone else seeing this happen

[Antimus]

9 hours ago, nige8021 said:

 

I think you're the one with an attitude, @KenONeill a forum user who has years of experience has given you a perfectly plausible cause, you might not see the map display jump but that doesn't mean the GPS data hasn't  

was asking if everyone gets this issue, if Ken is right then everyone with pacc would have this issue, which would make it unusable.

 

Do you have pacc? Do you have this issue?

[Antimus]

8 hours ago, KenONeill said:

OK, if you don't want help from a software engineer who has over 194 comments for each one you've made, and who works with GPS systems, who do you want hold from?

I just wanted to know if other pacc users were having this issue, If other users weren't having the same issue then there's obviously something wrong with my car or my setup, which I would need to get looked at.

 

Your message implied that everyone with pacc would be having the same problem as me, that's fine but I'd like someone with pacc to confirm that before I live with this issue, which basically means only using it on motorways, not great really.

[langers2k]

2 hours ago, Antimus said:

It's like the map data just switches from 70 to 60 to 70, but that must mean it happens to everyone with my map data and I can't find anyone else seeing this happen

 

I see that all the time - the speed limit data seems terrible for the dual carriageways I use. It quite often flips between 60 and 70 mph. As far as I know, the GPS receiver is working correctly and I've never noticed any drift or obvious GPS errors. Whilst I don't have pACC, I would fully expect it to follow those speed limits and therefore keep flipping...

 

At a guess, it treats all A roads as 60mph NSL and someone has done a poor job of labelling up 70mph sections

[Antimus]

1 hour ago, langers2k said:

 

I see that all the time - the speed limit data seems terrible for the dual carriageways I use. It quite often flips between 60 and 70 mph. As far as I know, the GPS receiver is working correctly and I've never noticed any drift or obvious GPS errors. Whilst I don't have pACC, I would fully expect it to follow those speed limits and therefore keep flipping...

 

At a guess, it treats all A roads as 60mph NSL and someone has done a poor job of labelling up 70mph sections

That was my worry, I looked and there's no information on their map data or where to suggest changes if you know it's wrong.

 

If I paid for this on a new car I'd be seriously ****ed to be honest

[langers2k]

I think you can submit corrections to HERE maps (source VW/Skoda use) but a quick search suggests it could be more complex than just incorrect limits. Just for example, take a look at this thread: https://forum.mapcreator.here.com/forums/topic/incorrect-speed-limits-causes-accidents/

 

Based from that, it appears HERE maps can have known roadwork areas with time based speed limits and the VW headunit applies them at all times rather than just the stated date/times. It's plausible that whenever VW do a map release, it'll have this data embedded and incorrectly applied by the headunit despite the roadworks being long gone etc 😕

 

You could try some older versions of the maps and see if you get different behaviour along some known issue areas? If so, it would definitely point at map data being the culprit.

 

That being said, I'm not how you would get it resolved. I guess potentially the headunit would need to ignore roadwork data but I doubt VW would make such a change.

[ords]

If you haven't done it already, go to other VW forums and ask the same question.

[john999boy]

Totally OT but as my incoming car will have predictive cruise control, is it possible to turn that 'feature' off?

[Antimus]

11 minutes ago, john999boy said:

Totally OT but as my incoming car will have predictive cruise control, is it possible to turn that 'feature' off?

I don't think so, I read somewhere that once you upgrade acc to pacc you can't go back to the 'radar only' adaptive cruise control system without a recode

[PetrolDave]

9 hours ago, Antimus said:

 It's like the map data just switches from 70 to 60 to 70

Related issue showing how GPS can jump between right and wrong speed limits - I have a Road Angel Pure speed camera warning device which until a SW update about a year ago always showed the correct speed limits when on major roads, but since the SW update frequently jumps to the speed limit of a parallel or even crossing road so I'll be doing 68mph on a 70mph road and it will suddenly tell me the speed limit is 30mph and then 50 yards later revert to the correct 70mph limit. I've learnt to ignore this annoying SW created false alert, BTW Road Angel have not even responded to me reporting it as a bug.

 

This shows how the explanation that @KenONeillhas suggested is not only entirely plausible, but is actually present in other GPS devices.

[Antimus]

No parallel or crossing roads though, made sure that wasn't the case, from @langers2kit looks like it might be map data, which is just impossible to fix

 

Problem is I can't just ignore it when the car lurches back to 60 without any warning