Volkswagen Adaptive Cruise Control Radar

SweetCaliber

Hi all,

Have a 2017 golf that is equipped with Adaptive Cruise Control (ACC). The radar sits behind the front VW badge.

At the start of January it started popping up on the dash that the ACC was unavailable so I thought nothing of it for a while and eventually took it to the VW dealer who said it had to be calibrated. Forked out 150 euro and all was well.

Well, for a month anyways. The other day the message reappeared and then went off after an hour, this happened over the course of 3 days and now today the message popped up and wont go away.

I've not driven the car over massive potholes or anything, just normal daily driving to work and back. Surely the issue is with the unit? I cannot fork out another 150 euro for calibration again after only a month.

Anyone have any idea if this is a common problem with these? I have warranty on the car still but the dealer said it isn't a warranty issue. But surely daily driving shouldn't mean I have to fork out 150 euro a month to get it calibrated?

It completely disables my cruise control when the message comes up.

Any advice?

sumo12

First off, and may sound silly but make sure the radar sensor is clean. Muck, dirt, snow etc will stop it working.

Don't think it's behind the badge on the VW's either, I think its just below the number plate in the lower grille. I may need correcting on this though..

SweetCaliber

sumo12 wrote: »

First off, and may sound silly but make sure the radar sensor is clean. Muck, dirt, snow etc will stop it working.

Don't think it's behind the badge on the VW's either, I think its just below the number plate in the lower grille. I may need correcting on this though..

Yeah cleaned it off and still showing the message.

On the MK7.5 its behind the badge now, stupid place to put it!

mickdw

We have a Passat with it behind the badge. Works well.
Only time it failed was when covered in snow.
It's not attached to the badge or grille either so it's protected fairly well and a knock to the grille shouldn't effect it.
Has your car ever had a front impact? If it was moving at all it would play up.

SweetCaliber

mickdw wrote: »

We have a Passat with it behind the badge. Works well.
Only time it failed was when covered in snow.
It's not attached to the badge or grille either so it's protected fairly well and a knock to the grille shouldn't effect it.
Has your car ever had a front impact? If it was moving at all it would play up.

Yeah I even go slow over speed bumps, never hit a pothole always avoid them. The first time it happened he said it was off by a degree. That I was "hitting too many potholes" or "parking under trees where branches fall off and it it?"

I've had the car over a year now and hit a total of 2 potholes I'd say, I always avoid them especially big ones.

Car never had a front impact, or any impact at all.

Am going to ring the dealer tomorrow, just expecting them to give stick over it blaming me for hitting potholes or having branches fall on it or stones hit it again like they did last time.

Im suspecting that the bracket that holds it may be faulty? Or possibly the unit itself?

mickdw

Ya something not right.
Is it still under warranty?
If so, take no crap re user damage unless they can show you damage on the car as it should be able to cope with a pothole.
We drive on the worst of country roads and no issue.

Truckermal

Jesus they are really talking rubbish about the branches! FFS you would need a huge Branch to disturb it and your front end would be in bits...

SweetCaliber

mickdw wrote: »

Ya something not right.
Is it still under warranty?
If so, take no crap re user damage unless they can show you damage on the car as it should be able to cope with a pothole.
We drive on the worst of country roads and no issue.

Yeah still under warranty until July this year so will be ringing them. Still feel ripped off paying 150 euro the first time, but just gave in, not this time though, not just under a month after it being calibrated.

Exactly, he did mention it is very sensitive but I dont rally the car around a track or trail, just normal city driving.

Truckermal wrote: »

Jesus they are really talking rubbish about the branches! FFS you would need a huge Branch to disturb it and your front end would be in bits...

Yeah I argued with them, rang VW head office and they fobbed me off also. Just gave in the first time as I enjoy cruise control for motorway driving that I do now and again.

mickdw

One other thing that could effect it. You didn't have a wheel alignment done recently did you. If someone got an alignment very wrong specially at the rear wheels, it would throw off the sensor angle of attack to road. Is your steering straight ahead when driving?

SweetCaliber

mickdw wrote: »

One other thing that could effect it. You didn't have a wheel alignment done recently did you. If someone got an alignment very wrong specially at the rear wheels, it would throw off the sensor angle of attack to road. Is your steering straight ahead when driving?

Nope, car drives straight, the dealer did align all the wheels before calibrating it and they were pretty spot on.

I hooked it up to VCDS, it was calibrated on the 30th January this year. It seems to be misaligned vertically again as it was before. I've included the VCDS results below:



Looking back on the VCDS error history, the last few times when it was disabled was due to dirt on the badge, hence why it would go off after a while but VCDS says that it is incorrectly positioned now.

I drove to Tesco today, no speedbumps, nothing :pac: :mad: Honestly don't know how it just changes position so easily.

Rusky rusky

mickdw wrote: »

One other thing that could effect it. You didn't have a wheel alignment done recently did you. If someone got an alignment very wrong specially at the rear wheels, it would throw off the sensor angle of attack to road. Is your steering straight ahead when driving?

If ops engine is 1.0 tsi or 1.6tdi - there’s no real wheel alignment due to torsion beam suspension. I drive on ****ty cork roads and have rattling suspension but it never affected the ACC. Same was during my 3y in mk7 and 5y in my wife’s polo (not acc but the same radar). Could be some electrical gremlins....

mickdw

Well if vcds is giving misalignment angles, it's not a sensor wiring fault.
Take it back and tell them there is something moving and it's not your doing.
If you could get a look yourself, it would be interesting to see if bracket is damaged or cracked or whether there is any other part of the structure moving.

mickdw

Rusky rusky wrote: »

If ops engine is 1.0 tsi or 1.6tdi - there’s no real wheel alignment due to torsion beam suspension. I drive on ****ty cork roads and have rattling suspension but it never affected the ACC. Same was during my 3y in mk7 and 5y in my wife’s polo (not acc but the same radar). Could be some electrical gremlins....

Still using that setup on golf?

SweetCaliber

mickdw wrote: »

Well if vcds is giving misalignment angles, it's not a sensor wiring fault.
Take it back and tell them there is something moving and it's not your doing.
If you could get a look yourself, it would be interesting to see if bracket is damaged or cracked or whether there is any other part of the structure moving.

I've no idea how to get the face of the badge off and wouldn't want to even try as I'd end up breaking something!

That's why I wish they kept it on the bottom grill, easy access but they had to go hide it....

Rusky rusky

mickdw wrote: »

Still using that setup on golf?

Started in mk7 with engines <120hp and is here to stay. Focus, Mazda 3 etc also have it.

Rusky rusky

SweetCaliber wrote: »

I've no idea how to get the face of the badge off and wouldn't want to even try as I'd end up breaking something!

That's why I wish they kept it on the bottom grill, easy access but they had to go hide it....

The exposed sensor was prone to stone damage, so I think it’s better it’s hidden behind the badge. Plus pedestrian recognition was added.

SweetCaliber

mickdw wrote: »

Still using that setup on golf?

Sure are.

Toyotafanboi

The four wheel alignment being checked and adjusted is a prerequisite of starting the radar calibration process so I'd say this has been checked.

For what its worth, €150 sounds reasonable for the job

The radar system on those is generally very reliable and even moreso on the 7.5's with the radar behind the badge.

We had seen issues with those in the past where they weren't clipped in right at the factory and the two lower clips were in place but the top two clips were in the lugs but not clipped fully home and one day the radar decides enough is enough and pops out, just a bit loose. It's only necessary to remove the badge to expose the radar for calibration but you sont need to touch it and at a glance it would look secure, so a tech may not have spotted it not clipped fully home.

I'd be checking that first. You probably dont want to interfere with the car yourself, but it you pop the badge off and take a pic to post here, you'd know by the look of it.

SweetCaliber

Toyotafanboi wrote: »

The four wheel alignment being checked and adjusted is a prerequisite of starting the radar calibration process so I'd say this has been checked.

For what its worth, €150 sounds reasonable for the job

The radar system on those is generally very reliable and even moreso on the 7.5's with the radar behind the badge.

We had seen issues with those in the past where they weren't clipped in right at the factory and the two lower clips were in place but the top two clips were in the lugs but not clipped fully home and one day the radar decides enough is enough and pops out, just a bit loose. It's only necessary to remove the badge to expose the radar for calibration but you sont need to touch it and at a glance it would look secure, so a tech may not have spotted it not clipped fully home.

I'd be checking that first. You probably dont want to interfere with the car yourself, but it you pop the badge off and take a pic to post here, you'd know by the look of it.

Im reasonably mechanically minded but hate trying to pop clips, is the badge just clipped on or do I need to remove it from the back? Im willing to pop it off but just dont want to break anything.

Toyotafanboi

The badge just prises off from the front, open the bonnet to make it a bit easier. Use a micro screwdriver or a plastic trim tool around the edge and it should pop off with a little persuasion.

MarkN

I presume if someone reverses into your radar while parking (with a tow bar for example) this could wreck the unit too?

User1998

I had the same issue with mine. I asked in the Golf GTI thread and was told realignment was around €150, and if that didn’t sort it a new radar would be around €1,000 I think. Something like a pigeon hitting it could break it. I never got it sorted in the end

mickdw

MarkN wrote: »

I presume if someone reverses into your radar while parking (with a tow bar for example) this could wreck the unit too?

On Passat for example, it's well clear of the badge so the grille could take quite a whack while doing no damage to radar.
I know this as a Passat in family suffered a broken grille after some mystery damage. Swapped out the grille easily and didn't have to touch the radar which was a relief.
The badge was fixed with 3 tabs to grille. Easy to remove from the back when grille was off. Might be tricky from front though.

SweetCaliber

Toyotafanboi wrote: »

The badge just prises off from the front, open the bonnet to make it a bit easier. Use a micro screwdriver or a plastic trim tool around the edge and it should pop off with a little persuasion.

Will do it in the morning with a bit of light, cheers!

SweetCaliber

So took off the badge this morning and the radar unit was out of the clip at the top was at an angle. Popped it in and it clicked.

Thought it was grand but message still showed on the dash. Checked the misalignment angle on vcds and it's now - 0.044 degrees.

Checked elsawin and the spec is between - 0.8 and +0.8 degrees so I've no idea now why it's still not working?

Toyotafanboi

Well if it was unclipped ame you clipped it tight, it'll definitely need recalibration now. Best thing to do would be to unveil it again and bring it back to the dealer :pac: at least you know what it likely is now.

sk8board

we have lots of experience with this error message, on our (now replaced) 171 golf - as others have said, VW initially had the ACC radar down low in the grill under the number plate, and in our case we had it recalibrated once under warranty and 9 months later it came back. As with the first time, we battled with VW ireland to convince them there was no visible damage (the garage obviously backed that up), to do it under warranty which they did, and 2 days later the error returned for a 3rd time. This time they said the bracket holding it had a hairline crack. I can't imagine how and certainly we didn't notice any damage, even crawling under the car (nor did the garage notice in the two times they recalibrated it previously).
This was last December, and they wanted €325 to recalibrated outside of warranty - apparently they have one machine between the 3 dublin garages.

Thankfully we already had the car traded for a new golf, and the salesman didn't care as they could just fix it themselves after taking it back in. the new one has the ACC radar moved up higher, behind the VW badge. No issues yet of course, but it seems like a better solution - and lets face it they wouldn't have moved it on the mk7.5 if it wasn't an issue for a lot of people.

as other have said, €150 seems cheap for the recalibrating in my experience

mickdw

SweetCaliber wrote: »

So took off the badge this morning and the radar unit was out of the clip at the top was at an angle. Popped it in and it clicked.

Thought it was grand but message still showed on the dash. Checked the misalignment angle on vcds and it's now - 0.044 degrees.

Checked elsawin and the spec is between - 0.8 and +0.8 degrees so I've no idea now why it's still not working?

The reading was also 0.044 degree on your earlier screenshot so you must not be getting readings from its current position.

kirving

The -0.044° looks to be the horizontal misalignment.

The "performed adjustment-Misalignment angle" of -1.82° is exactly half of the "performed adjustment-Vertical offset angle" of 3.64°.

Maybe a coincidence, but seems unlikely to me.

Was this a manual process to input those values? Could a setting have been put in the wrong place (as those are different parameters), or was a negative value input instead of positive.

Without knowing the specifics of each parameter, and since you've now fixed the bracket problem, I would think that the car is trying to perform and on-line calibration - which it can't seem to do.

Have you changed any values via VCDS?

SweetCaliber

Kevin Irving wrote: »

The -0.044° looks to be the horizontal misalignment.

The "performed adjustment-Misalignment angle" of -1.82° is exactly half of the "performed adjustment-Vertical offset angle" of 3.64°.

Maybe a coincidence, but seems unlikely to me.

Was this a manual process to input those values? Could a setting have been put in the wrong place (as those are different parameters), or was a negative value input instead of positive.

Without knowing the specifics of each parameter, and since you've now fixed the bracket problem, I would think that the car is trying to perform and on-line calibration - which it can't seem to do.

Have you changed any values via VCDS?

Cant change the values in VCDS, I know with the older radars you could reset the misalignment angle but not anymore. Seems you need to use ODIN to change any values related to it.

Strage how the angles haven't changed even though I moved it back into place.

Also strange how the reading VCDS is getting is in spec, surely the car is seeing the same reading so its a mystery why the error is showing.

Will contact the dealer in the morning, will stand my ground that nothing touched the badge or radar (which it technically didn't) and will put it back to the position it was at before I popped it in.


For those saying 150 isn't a bad price, I will agree. One VW dealer wanted 300 to do it (wont name).

However spending 150 to get it done a month after it was re-calibrated is what annoys me, it seems their competence to not make sure the unit is secure is the problem, just trying to get that through to them without saying I took off the badge cover will be tricky.

Tropheus

Are there any error codes in VCDS that need clearing?

SweetCaliber

Tropheus wrote: »

Are there any error codes in VCDS that need clearing?

0791 - Sensor for Automatic Distance Regulation; Incorrectly Positioned.

No matter how many times I clear it, it just comes back straight away.