Potential safety issue with T6.1 Automatic Cruise Control

[Buddy69]

Hello this thread is specifically geared towards T6.1 California Coast owners 2020 onwards. I have had to ask VW to replace my ACC front sensor under warranty, due to a safety fault. Three times it failed at motorway speeds. This was confirmed by VW technicians as faulty yet the vehicle had only covered 300 miles! Therefore the unit itself may need to be assessed by your local dealership. Best to be safe out there guys.

 

[WelshGas]

Hello this thread is specifically geared towards T6.1 California Coast owners 2020 onwards. I have had to ask VW to replace my ACC front sensor under warranty, due to a safety fault. Three times it failed at motorway speeds. This was confirmed by VW technicians as faulty yet the vehicle had only covered 300 miles! Therefore the unit itself may need to be assessed by your local dealership. Best to be safe out there guys.

A little more information would be helpful.
In what way did it fail?
In what way is it a Safety Fault?
If it stops working then I wouldn't class that as a safety fault as there are numerous cars on the road without ACC and they can hardly be classed as Unsafe.

 

[Buddy69]

Whilst driving on the motorway at motorway speeds, I engaged the ACC. All was fine until I noticed queuing traffic ahead , well within range of the ACC to display vehicle detected. And begin to as it should automatically apply the brakes. Rather disconcertingly I had to do this manually. The dashboard then read ACC fault. Despite when safe to do so switching the vehicles ignition off and on several times. This is therefore most certainly a 'safety fault'. As it designed to recognise such dangers. Re the other vehicle comment please read initial post Mr Welshgas. The information is specifically for the vehicles denoted VW Coast T6.1 2020 onwards fitted with ACC. By default if you don't have ACC fitted your vehicle is safe and this post is irrelevant to you. However, If this post helps said owners stay safe then fantastic.

 

[WelshGas]

Whilst driving on the motorway at motorway speeds, I engaged the ACC. All was fine until I noticed queuing traffic ahead , well within range of the ACC to display vehicle detected. And begin to as it should automatically apply the brakes. Rather disconcertingly I had to do this manually. The dashboard then read ACC fault. Despite when safe to do so switching the vehicles ignition off and on several times. This is therefore most certainly a 'safety fault'. As it designed to recognise such dangers. Re the other vehicle comment please read initial post Mr Welshgas. The information is specifically for the vehicles denoted VW Coast T6.1 2020 onwards fitted with ACC. By default if you don't have ACC fitted your vehicle is safe and this post is irrelevant to you. However, If this post helps said owners stay safe then fantastic.

Now you have explained the fault it makes sense to describe it as a Safety Fault. However that wasn't clear in your original post.
Others have had problems with the ACC switching Off, which is what it is supposed to do if it detects a fault. I would not describe that as a "Safety" fault, just a Fault.
I did read your initial post and nowhere do you describe that the vehicle failed to slow when approaching slower moving traffic.

 

[B J G]

Now with full fault information it highlights the danger of 'expecting' Automatic Devices to take care of what would be normal driving practices.

 

[kurienp]

Hello this thread is specifically geared towards T6.1 California Coast owners 2020 onwards. I have had to ask VW to replace my ACC front sensor under warranty, due to a safety fault. Three times it failed at motorway speeds. This was confirmed by VW technicians as faulty yet the vehicle had only covered 300 miles! Therefore the unit itself may need to be assessed by your local dealership. Best to be safe out there guys.

@Buddy69 , a request for a correction - ACC is Adaptive Cruise Control and not Automatic. If you are able to change the subject in your thread title, it will help with the forum search of bringing up relevant results during a search.

Thanks.

 

[Buddy69]

In reply to kurienp, just semantics my mate.I Googled it and you are rite however ' ACC automatically adjusts the speed of your car to match the speed of the car in front of you. If the car ahead slows down, ACC can automatically match it. Once the car ahead moves out of your lane or accelerates beyond your car's set speed, your ACC allows your car to return to the speed that you have set.

 

[andyinluton]

In reply to kurienp, just semantics my mate.I Googled it and you are rite however ' ACC automatically adjusts the speed of your car to match the speed of the car in front of you. If the car ahead slows down, ACC can automatically match it. Once the car ahead moves out of your lane or accelerates beyond your car's set speed, your ACC allows your car to return to the speed that you have set.

Its not just semantics, the title of the thread is what search engine looks at.
No-one will be searching for Automatic Cruise Control hence the request to edit the title.

 

[Loz]

Are you saying that the ACC failed to stop for a stationary queue of traffic?

If so, that is how it works and not a fault, the manual clearly says it does not recognise stopped traffic, as long as the vehicle in front is moving it will slow you down.

The City braking that can stop the vehicle if you try and run into a stationary object or a person only operates up to 18MPH

 

[B J G]

Are you saying that the ACC failed to stop for a stationary queue of traffic?

If so, that is how it works and not a fault, the manual clearly says it does not recognise stopped traffic, as long as the vehicle in front is moving it will slow you down.

The City braking that can stop the vehicle if you try and run into a stationary object or a person only operates up to 18MPH

Would it not slow the vehicle to a speed cut off point then the City braking take over?

Question as I don't know the answer.

 

[yossarian]

Cruise Control | Volkswagen UK

Discover how cruise control works electronically to regulate your car's speed, making journeys more comfortable & safer. Learn more at Volkswagen today.

www.volkswagen.co.uk

A marketing description but some salient points. Max 200m detection range and 30% of available braking. "Motorway speeds" are around 40m/s so around 5 seconds away from impacting something stationary.

Typical stopping distance from 70mph is about 100m.

Van braking distances explained – loaded vans take 33% longer to stop

Expert analysis of van stopping distances on Parkers, with info from the Highway Code and loaded van braking distance research from VW

www.parkers.co.uk

 

[andyinluton]

Would it not slow the vehicle to a speed cut off point then the City braking take over?

Question as I don't know the answer.

I don't know what system does what, but from using mine it seems the ACC does absolutely everything it can to avoid actually coming to a stop, including dropping to 1st gear & crawling at 1mph up to the car in front.

Travelling in a 30mph limit it certainly does see a stationary queue of traffic & slows down accordingly. What I wouldn't trust it to see is a stationary car at motorway speeds.

 

[GrumpyGranddad]

Whilst driving on the motorway at motorway speeds, I engaged the ACC. All was fine until I noticed queuing traffic ahead , well within range of the ACC to display vehicle detected. And begin to as it should automatically apply the brakes. Rather disconcertingly I had to do this manually. The dashboard then read ACC fault. Despite when safe to do so switching the vehicles ignition off and on several times. This is therefore most certainly a 'safety fault'. As it designed to recognise such dangers. Re the other vehicle comment please read initial post Mr Welshgas. The information is specifically for the vehicles denoted VW Coast T6.1 2020 onwards fitted with ACC. By default if you don't have ACC fitted your vehicle is safe and this post is irrelevant to you. However, If this post helps said owners stay safe then fantastic.

I think the issue is that if you are travelling at speed on an empty motorway and you switch on ACC, the system has no reference point i.e. a vehicle in front of you to work on. It has a maximum range.
If you then come across a queue of stationary traffic the ACC system obviously can’t refer to a non existent reference point so won’t slow the van down.
Mine works faultlessly but obviously, total reliance should not be placed on driving aids.

 

[Buddy69]

Hello and thankyou for all your armchair 'expert ' input into solving the issue. This forum it seems revels zoneing in on critiscizing any new posters, however important the issue. Note not one positive reply to say thanks for the heads up re a real world safety issue. Its all your fault etc read the manual..doest seem broken to me.. classic cognitive dissonance.However you can all rest now and be assured that I have taken the advice of the real experts. The professional trained ones from VW who have diagnosed on a VW diagnostic computer. That the part is well yes 'broken' and as such was replaced. So forum members were the VW technicians and the computer diagnostic wrong. Or are you rite and they just replaced it to keep Hannover parts depot busy.

 

[WelshGas]

Wow.

 

[Dodge1311]

Mine likes to slow down if i am in the right hand lane overtaking. It sees the car on the left and gets confused. As per VW technical support advice wipe the radar cover with a cloth and try again. It’s fine for undertaking so may just adjust my driving to always pass on the left.

 

[GrumpyGranddad]

Hello and thankyou for all your armchair 'expert ' input into solving the issue. This forum it seems revels zoneing in on critiscizing any new posters, however important the issue. Note not one positive reply to say thanks for the heads up re a real world safety issue. Its all your fault etc read the manual..doest seem broken to me.. classic cognitive dissonance.However you can all rest now and be assured that I have taken the advice of the real experts. The professional trained ones from VW who have diagnosed on a VW diagnostic computer. That the part is well yes 'broken' and as such was replaced. So forum members were the VW technicians and the computer diagnostic wrong. Or are you rite and they just replaced it to keep Hannover parts depot busy.

Don’t be offended @Buddy69, i‘m sure that most people’s responses are made with good intentions and not intended to challenge you.

For reference the following is an extract from VW’s description of ACC (available on the web). Note the last line.

Using the signals from the radar sensor, the control unit computes the distance to the vehicle ahead and your car's speed relative to it. It also works out its lateral position on multi-lane roads. If there are several vehicles within the sensor's field of coverage at the same time, this information is used to select which of the vehicles the system should track. The radar sensor is not capable of detecting stationary obstructions, such as the end of a tailback or crash barriers, however.

 

[Loz]

How F###ing RUDE!

I responded to educate you on how the system actually works, so that you don’t have a serious accident with a system you obviously don’t understand and you respond with that!

Unbelievable!

 

[yossarian]

How F###ing RUDE!

I responded to educate you on how the system actually works, so that you don’t have a serious accident with a system you obviously don’t understand and you respond with that!

Unbelievable!

@Buddy69 read through @Loz 's 5000 odd posts; it's not easy to get this sort of reaction.

The thrust of my poorly explained post above was that I would not like to have you driving behind me in a tailback relying on some system that you clearly don't understand. I hope that you can perhaps take on board that the predominant safety issue that most people saw here was your expectations of the ACC system, not the specific sensor failure that you experienced.

 

[kurienp]

Hello and thankyou for all your armchair 'expert ' input into solving the issue. This forum it seems revels zoneing in on critiscizing any new posters, however important the issue. Note not one positive reply to say thanks for the heads up re a real world safety issue. Its all your fault etc read the manual..doest seem broken to me.. classic cognitive dissonance.However you can all rest now and be assured that I have taken the advice of the real experts. The professional trained ones from VW who have diagnosed on a VW diagnostic computer. That the part is well yes 'broken' and as such was replaced. So forum members were the VW technicians and the computer diagnostic wrong. Or are you rite and they just replaced it to keep Hannover parts depot busy.

@Buddy69 , that is extremely rude of you and I think you owe an apology to all those on here who have tried to help you.
- my post was a request to change the title
- Yossarian went to the extent of finding articles to explain the details to you
- GGD further explained details to you
- Loz's post was the best explanation on how it works

If you want us all to fall to your low levels and buddy up to you to blame it on someone - sorry, we will not. We have the ability to think, assimilate information and - most importantly - with humility, "learn" from the experiences and knowledge of others.

Remember, VW may be just replacing the part to keep you 'busy' and away from their workshop. Re-read the posts above, learn how ACC works and you will be a happy Cali user.

 

[soulstyledevon]

ACC
A Collision Coming

I’m really not a fan...!!!

I can understand the O/P’s point of view to an extent. But that’s because ACC puts you mind set into trusting something that makes you think you can take your eye of the ball.
That it will slow you down automatically.
However, you still need to be fully in control and ready to action.

IMO, standard cruise is far safer as the driver is fully reliant on himself to action and not relying on the computer to make any inputs...

Glad the fault sensor is fixed O/P, but understand points were made to fully understand the issue and create awareness on the ACC system.

 

[ChocolateEclair]

ACC
A Collision Coming

I’m really not a fan...!!!

I can understand the O/P’s point of view to an extent. But that’s because ACC puts you mind set into trusting something that makes you think you can take your eye of the ball.
That it will slow you down automatically.
However, you still need to be fully in control and ready to action.

IMO, standard cruise is far safer as the driver is fully reliant on himself to action and not relying on the computer to make any inputs...

Glad the fault sensor is fixed O/P, but understand points were made to fully understand the issue and create awareness on the ACC system.

I agree.

I had a 'moment' on the M27 with ACC enabled - it did not slow down when the pimped up BMW in front of me braked. I was travelling about 60mph at the time and it was about 40 metres in front of me. If I hadn't intervened I'm sure I would have hit it.

It was wrapped in some sort of matt black plastic and the ACC just did not see it (no car symbol on the dash).

It's never happened since and I still use ACC but don't ever trust it 100%.

 

[GrumpyGranddad]

I think we all agree, so time for a VWCC group hug (Boris says that’s OK).

ACC is quite simply a ‘driver aid’, it does not replace the driver. Even automatic windscreen wipers occassionally need a manual intervention

On a busy motorway I think ACC is great as it eliminates the constant set/resume of bog standard Cruise Control.

 

[soulstyledevon]

I agree.

I had a 'moment' on the M27 with ACC enabled - it did not slow down when the pimped up BMW in front of me braked. I was travelling about 60mph at the time and it was about 40 metres in front of me. If I hadn't intervened I'm sure I would have hit it.

It was wrapped in some sort of matt black plastic and the ACC just did not see it (no car symbol on the dash).

It's never happened since and I still use ACC but don't ever trust it 100%.

Yes
I’ve experienced that on the loan vehicle I had.
I find the system makes the driver complacent too.

Automation only works if everything is automated.
I used to work for Peugeot many many moons ago. The robotic equipment for assembly was never mixed with the human.
Yes they completed a task, which then passed over to human assembly. But you never had both working together as such...

 

[Calimili]

ACC
A Collision Coming

I’m really not a fan...!!!

I can understand the O/P’s point of view to an extent. But that’s because ACC puts you mind set into trusting something that makes you think you can take your eye of the ball.
That it will slow you down automatically.
However, you still need to be fully in control and ready to action.

IMO, standard cruise is far safer as the driver is fully reliant on himself to action and not relying on the computer to make any inputs...

Glad the fault sensor is fixed O/P, but understand points were made to fully understand the issue and create awareness on the ACC system.

I agree with you. That's why I don't even bother with side lane assist and other gizmos. They make you lazy. Even reversing with the Park Distance Control in my car I don't bother looking backwards. With the Cali at least I have a rear cam.
People need to keep paying attention on the road , and not relying on assistants. They help but don't substitute the human.
Wait until they provide the Autopilot, than we'll see accident cases where the driver was cooking and nobody at the wheel, if Tesla is any indication..