ACC and Lane Assist unavailable, 2018 Passat B8

[guyburns]

My 2018 Passat has just developed a fault that says ACC and Lane Assist are unavailable. I've booked a one-hour diagnosis session with VW for 24 November ($190), but then I thought maybe I should get into this VCDS thing myself.

I've spent several hours looking into this and I think I need a Hex V2 for $408.
(VCDS HEX-V2 (3 VIN) (https://www.autoequipment.com.au/scan-tools-and-accessories/vcds/vcds-hex-v2-3-vin)

On the Ross-Tech site section 1.8, they say I can run the software on my Mac using BootCamp.
(Ross-Tech: FAQ (https://www.ross-tech.com/vag-com/faq_1.php#1.1))

Under section 1.13 they also say I'll need...
a good Repair Manual containing the Native Scan-Tool procedures for your car...

and they suggest Erwin. Well, after exploring the Erwin site for 30 minutes and not getting very far, I came away thinking: "Bloody ridiculous – 7 Euros for 1 hour access to one article". And I couldn't even locate a list of available articles.

• So then I looked up my car at Haines.
(Volkswagen Passat VIII (3G, CB) Haynes Repair Manuals & Guides (https://haynes.com/en-au/volkswagen/passat-viii-3g-cb/2015)). They say (under the Autofix Explained tab)...

So, we’re putting an electronics diagnosis module in the hands of DIY repairers for the first time. Enter a fault code and follow the instructions to test components in order, and establish the likely cause of a problem. Our tool goes far beyond what commonly available fault code readers offer, and puts you, the car owner, back in control. Even if you choose not to complete the repair yourself, you will know exactly what the problem is when you hand it over to a workshop.

Questions
Q1. Is the Hex V2 only the first part of what's needed to be able to resolve my problem, or at least point me in the right direction?

Q2. Do I really need an additional manual, say from Haines?

Q3. What extra information would be contained in the manual that the Hex V2 lacks?

Q4. At present, I'm being warned about an overdue oil change, which I'll do myself when I get around to it. Is that warning going to disappear when I change the oil, or will I need the Hex V2 to remove the warning?

Q5. This video (2014 VW Passat with an adaptive cruise control issue - YouTube (https://www.youtube.com/watch?v=S7UtfTPrT3k)) suggests that if the radar unit is faulty, instead of fixing that at great expense, it might be possible to recode so that the car just has normal cruise control, by simply removing the Adaptive part (see 2.10+). Does anyone know how to do that?

Any suggestions most appreciated.

[Flipper Dog]

You need to get your Passat properly diagnose first.
It could be anything from faulty hardware or electronics to a simple re-calibration/re-set of the ACC module. A diagnostic report will give you that information to go forward.
Audi A8L adaptive cruise control system reset - YouTube (https://youtu.be/hZBZMnHeNOw)
ACC calibration - Audi VW radar alignment DIY (C1103) - YouTube (https://youtu.be/SlmP7EBCtyI)
Some videos to get you started.

To your questions.
Q1. The diagnostic device, be VCDS or something cheaper, is the first part of finding your issue. It will provide details on where your fault is and the codes related to that for you to research a path for repair.
Q2. Workshop manuals help navigate your way around the vehicle. ERWIN works by placing in your VIN and then downloading all the files which appear related to that VIN. The search function, unless you are familiar with using, can take some practice using.
Q3. Dedicated web sites, such as Ross Tech or forums, will provide you better instructions for coding than workshop manuals. I like to think that if you can see it then the manual will show where and what it is and how to get to it.
Q4. Most diagnostic devices will allow you the ability to reset warnings such as oil service.
Q5. This is a start ACC Delete using vcds, audi SQ5 - YouTube (https://youtu.be/AgkjK_awk1Q) to assist in disabling ACC. You need to research further on forums or try ODB11 or Ross Tech's sites for guidance.

[DV52]

@guyburn: Hi.

hmm....... maybe I can add a slightly different insight to the sage answers already provided?

Are you really sure that you want to throw $408 at a VCDS cable at this stage in your investigations? Don't get me wrong, I like VCDS (also consider OBDeleven - each different device has its own advantages and disadvantages) - it's just that buying a diagnostic device might not be useful in solving this problem.

The alternative approach is to use the diagnostic device of a local forum colleague that lives close. Again, it seems to me that at this time, you need information about the problem, rather than assuming that a diagnostic device will be useful in fixing the problem.

My suggestion is driven by the early (and scant) information provided in your post. Of course anything is possible and I'm guessing - but if both ACC and Lane Assist isn't working, it's entirely possible that the module for your front-facing camera has lost calibration, maybe?. This is a not uncommon problem and if this is the cause of the fault- VCDS won't fix it (you need a dealer alignment tool)

As you may be aware, this forum has a "pimping" facility for members that seek diagnostic services from other colleagues. If after you obtain a scan report from a colleague, it shows that a diagnostic cable will be useful in fixing the problem - then maybe consider buying the device. Else, use the saved $408 potential expense to fund the cost of the dealer charges (it shouldn't be this expensive - only needs less than 1 x hour of the dealer's master-tech time to re-calibrate the hexA5 module)!

Don

PS: On the matter of the ERWIN site and as previously suggested - you should consider this to be a download site ONLY. Don't do any fault finding on-line while the subscription time is active. The subscription time should be used SOLELY to download as many .PDF documents as possible. After you have these files on your local PC/laptop, interrogate the documents at your leisure!

IMO, the most important document for this type of fault is the wiring diagram for the car. I have no idea why, but VW calls this file Basic Equipment.

[guyburns]

Thanks for the suggestions.

I had to cancel the Nov 24 appointment because I needed the car, so I'll provide more information while I wait for the next appointment, in the hope that I can work out where the problem lies.

Here's what happened. I was driving on a highway and ACC and Lane Assistant were working fine. I don't recall going over any bumps that may have upset the radar. I slowed down and turned onto a side road without lane markings. After a few kilometres I tried to turn on the cruise control again, but nothing happened. The message said "ACC and Lane Assist unavailable." I assumed it was because there were no lane markings. But they haven't come back. When I try to turn on ACC I get either the "unavailable" message or one that says "ACC and Lane Assists deactivated".

Something else that might have contributed, because I read somewhere if a radar unit is disconnected or blocked for a period of time, it may be deactivated because the computer thinks it has been put in another vehicle and therefore needs calibration. Anyway, I had a bungee cord attached underneath the front of the car, only lightly stretched, to help keep a load of timber in place. That bungee cord was within a few centimetres of the right-side, front-facing sensor (not the radar unit behind the badge), and the bungee may have moved a bit and actually covered the sensor.

If that had happened, say when I turned onto the side road, might that blockage have caused ACC and Lane Assist to be permanently deactivated?