Adaptive cruise intermittent fault

[GrahamB]

I think I have seen this issue posted previously but I couldn’t find it with a search. Recently on a few longer trips with ACC on, I have noticed the van slowing and preventing an overtake on a dual carriageway, showing a car to the left in the display. Also at that moment it was showing 110 as the speed limit (presumably meaning kph). So it had apparently decided it must be in France and that an overtake on the right would be an undertake (which the ACC wont allow). I could put my foot back on the gas to get by but it was annoying when it kept happening. After a while it seemed to sort itself out.

Anyone else had this and know what the fix is? I dont believe it can be radar calibration because the problem is intermittent.

 

[subthree]

Yep, had exactly the same thing when travelling to Europe from the UK. As you say after a few minutes it seems to sort itself out. I assume it is GPS based.

 

[GrahamB]

Thanks @subthree - do you mean that when crossing the channel it takes a while to work out where it is and then sorts itself out? That would tend to confirm my theory that its more likely the GPS that is playing up and confusing the ACC. I maybe didn't make it clear, but this has been happening in the UK in my case, without having crossed the water!

 

[The Tall Luthier]

Exactly the same when I arrived in the EU. Reasonably short lived, after a flurry of false positives.
The same happened ont return to the uk. Again short lived.

 

[subthree]

Thanks @subthree - do you mean that when crossing the channel it takes a while to work out where it is and then sorts itself out? That would tend to confirm my theory that its more likely the GPS that is playing up and confusing the ACC. I maybe didn't make it clear, but this has been happening in the UK in my case, without having crossed the water!

Yes, after crossing three channel.

Ah, if it is happening in the UK then something isn't right!

 

[GrahamB]

Thanks guys, I’ll get it checked out when its next in the workshop.

 

[Hawthorn37]

If you have a Carista module, you can directly set the overtaking side left/right. I’ve not done this (not yet been to Europe in the van) but it would appear you should get an immediate response, if this concerns anyone.

 

[GrahamB]

If you have a Carista module, you can directly set the overtaking side left/right. I’ve not done this (not yet been to Europe in the van) but it would appear you should get an immediate response, if this concerns anyone.

Interesting, I do have Carista, so I could try that. Presumably it would then override GPS location correction and it would need resetting for Europe.

 

[Hawthorn37]

That’s how I understand it, yes.

 

[Rololux]

Had exactly this problem last week on a trip to the uk. Driving towards Ashford after the tunnel, van would not pass vehicles traveling slowly on the left. Override by forcing the accelerator - settled after a few km. Returning to France, same issue in reverse - could not pass vehicles on the right. Also sorted after a few km. Never had this before - must be a recent software update issue!

 

[GrumpyGranddad]

I’ve had the 110 Speed Limit come up on my dash. I wonder if it is because I have passed an EU lorry displaying a sticker and the California has read it as if it was a speed limit sign?

 

[GrahamB]

Had exactly this problem last week on a trip to the uk. Driving towards Ashford after the tunnel, van would not pass vehicles traveling slowly on the left. Override by forcing the accelerator - settled after a few km. Returning to France, same issue in reverse - could not pass vehicles on the right. Also sorted after a few km. Never had this before - must be a recent software update issue!

If I understand it correctly that is the expected behaviour - the van is recognising the change of traffic direction after a short time, informed by GPS. My problem is its happenibg without leaving the UK!

 

[GrahamB]

I’ve had the 110 Speed Limit come up on my dash. I wonder if it is because I have passed an EU lorry displaying a sticker and the California has read it as if it was a speed limit sign?

View attachment 92367

It might do that, but surely that wouldn’t cause it to think it had teleported to France?!

 

[Hawthorn37]

I’ve had the 110 Speed Limit come up on my dash. I wonder if it is because I have passed an EU lorry displaying a sticker and the California has read it as if it was a speed limit sign?

View attachment 92367

Never mind you ACC, can you imagine the chaos random speed signs could cause with driverless cars . I’ve had a couple of cars with Road sign recognition, and just lets say they’re not exactly reliable.

 

[GrahamB]

Never mind you ACC, can you imagine the chaos random speed signs could cause with driverless cars . I’ve had a couple of cars with Road sign recognition, and just lets say they’re not exactly reliable.

Not to mention the potential for the driverless car to think it was in Europe and switch to the wrong side of the road

 

[Dodge1311]

Mine does this at least once a month and when it happens it stays that way until i stop for a while. VW say "no fault found" each time it goes in.

 

[rpevans99]

I had this on a VW Golf. It would happen intermittently. Gave up in the end. Just positioned my foot to tap the accelerator to override. Don't have the car anymore.

 

[MeltedGoldfish]

Likewise I had this happen on a Golf hire car last year. Wouldn’t overtake (but would undertake), and kept reading the national speed limit sign (70mph on dual carriageway) as 70kph, so would suddenly brake to 44mph (70kph). Pulled over at services and stopped/restarted ignition and I was magically back in the UK again.

No idea what the trigger was (I had a suspicion being stuck behind a European truck with a “60kph” sign on the back for 10 mins in traffic might have triggered it, but not convinced the system’s that clever),and no idea what the solution is, but clearly a bug in the VW software.

I have posted this on another similar thread, if that’s the one you’re thinking of.


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[WelshGas]

This problem could be due to electronic interference upsetting the GPS signal in an abnormal way causing a reset of GPS position to baseline Europe. Navigation might continue as there is an element of inertial guidance built in to cope with a normal signal loss of GPS due to high rise buildings or tunnels etc.

Until the system then receives a signal from a number of GPS satellites to recalculate its position it believes you are still in Europe..

I wonder if any European owners experience the equivalent whilst driving in Europe only, not crossing the channel.

 

[MeltedGoldfish]

This problem could be due to electronic interference upsetting the GPS signal in an abnormal way causing a reset of GPS position to baseline Europe. Navigation might continue as there is an element of inertial guidance built in to cope with a normal signal loss of GPS due to high rise buildings or tunnels etc.

Until the system then receives a signal from a number of GPS satellites to recalculate its position it believes you are still in Europe..

I wonder if any European owners experience the equivalent whilst driving in Europe only, not crossing the channel.

Interesting thought [mention]WelshGas [/mention] I have a fairly good understanding of aircraft GPS and INS, but hadn’t thought too much about car ones having INS backup! I have had a previous car Sat nav fail and put me in the centre of Brussels though.

As it happens, I did have a coincidental built-in Sat Nav fault on this occasion - the map showed me in the correct place, but the junction voice guidance was one step ahead. Eg when going from M1 to M69 it said turn onto M6. When going from M69 to M6 it said turn onto M42. When reaching the M6/M42 junction it said turn onto M5 etc etc. I had assumed they were completely unrelated faults, and pretty sure the Sat nav one continued after I’d reset the ACC one, but now wondering whether there may have been a connection. Somehow. Will have to ponder on it!


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[coopersd]

Yep, had exactly the same thing when travelling to Europe from the UK. As you say after a few minutes it seems to sort itself out. I assume it is GPS based.

Hi, did you need to fit headlight deflection when travelling to Europe or do the headlights adapt to driving on the right based on the GPS?

 

[WelshGas]

Hi, did you need to fit headlight deflection when travelling to Europe or do the headlights adapt to driving on the right based on the GPS?

If you have LED headlights - then nothing needs to be done. They are flat beamed.

If you have Non-LED then you need deflectors. There is no adjustment.

The T6 with LED has Travel Mode via MFD

The T5.1 with Xenon headlights needs adjustment.

 

[coopersd]

If you have LED headlights - then nothing needs to be done. They are flat beamed.

If you have Non-LED then you need deflectors. There is no adjustment.

The T6 with LED has Travel Mode via MFD

The T5.1 with Xenon headlights needs adjustment.

Thanks, that’s helpful