[teenup91]

I was driving earlier today and all of a sudden my ACC stopped working. After I stopped, I looked at the front of my car and the emblem fell off. I believe that the ACC module is still connected, but I'm not 100% sure.

Is the emblem required for the ACC to work?

 

[Rabbitvw25]

That sucks. I’d say you’d need to get an oem cover either way, so see if it starts working again, maybe disconnect the battery for cpl hrs when you put the new one in and hopefully it starts working again.

 

[BSM]

maybe disconnect the battery for cpl hrs

That is the exact opposite of what you should do on any modern car unless you’re ready to zero your passenger seat weight sensor, re-learn your idle, calibrate your steering angle sensor, re-train your transmission shift points, and perform any number of other procedures which require an expensive scantool.

 

[burgsprinta]

That is the exact opposite of what you should do on any modern car unless you’re ready to zero your passenger seat weight sensor, re-learn your idle, calibrate your steering angle sensor, re-train your transmission shift points, and perform any number of other procedures which require an expensive scantool.

It learns all that stuff on its own, automatically. No scan tool needed. I've left my battery disconnected multiple times. It causes absolutely zero issues. You just have to raise the windows all the way up and down to relearn the auto up/down, or it'll just happen naturally the next time you use them. And either turn the steering wheel lock to lock, or drive it around the block. Shut it off, and restart, so the cruise control and emergency braking work again (you'll get an error message otherwise).

Our jeep is fairly new too (2018), and I've also disconnected it's battery. And my Subaru was a 2017, and I also disconnected its battery for extended periods. Nothing bad ever happened. After a short drive, or letting the car run for a while, all relearned on their own. What car doesn't? That would be a serious problem if it were a real issue. Disconnecting the battery does not hurt anything on these cars. You lose your clock setting, that's it. You don't even lose your radio presets on the vw.

I think after disconnecting, for the first few restarts, you have to hold the start/stop button for the car to start, instead of just tapping it. But it learns that on its own too. Disconnecting the battery doesn't break anything on these cars.

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[Laccos]

Thats nuts. The VW badge does have a purpose of keeping the sensor clean. When the bomb cyclone blizzard happened last year my badge lightly froze over on the drive home and my front assist threw its hands up in defeat. Whos to say how much dirt it takes to blind the thing.

 

[BSM]

How are you checking the calibration of all these systems? And where are you getting your service information? Some systems can self-calibrate. Some systems can detect that they’ve lost calibration. But some will just silently malfunction when they’re needed most - for example, you probably won’t know that your yaw rate sensor is out of whack until the stability control system is trying to save your bacon.

 

[Laccos]

Front end assist is using physical storage on the vehicle for wheel alignment data as well as sensor settings. Modern cars have memory on board specifically to keep safety systems settings in the event of loss of power. You might not have seen my posts last year about this when people were removing their bumper covers for fog light retrofits and all that fun stuff where I was warning them to not turn the vehicle on with the frontend assist sensor disconnected. Having the sensor disconnected and turning the car on wipes everything and forces an error state to which you have to then go get the $500 all wheel alignment and sensor recalibrated. Where are you getting this information from, because if you are correct then i certainly will be taking my vehicle in for service. Looking through my owner manual, I see nothing indicating what you have said is correct. Perhaps you have found a page I havent though so please correct me if I am wrong.

Im not being snarky here, youve genuinely peaked my interest because if what you say is true it seems truly unintuitive to not use the on board memory for all active safety features or at the least display malfunctioning system if they cant self calibrate.

 

[Rabbitvw25]

The reason I said to disconnect the battery is I saw a lot of people changing their grills out without disconnecting the battery and getting that error.
Also to caveat on not disconnecting the battery due to having to calibrate everything- I would think that modern ecu’s are smart enough to do that automatically. If following the logic that you have to recalibrate everything for safety systems to work, then most of the cars on the road would be unsafe due to people changing batteries either themselves or places like autozone who do no recalibrations.

 

[burgsprinta]

How are you checking the calibration of all these systems? And where are you getting your service information? Some systems can self-calibrate. Some systems can detect that they’ve lost calibration. But some will just silently malfunction when they’re needed most - for example, you probably won’t know that your yaw rate sensor is out of whack until the stability control system is trying to save your bacon.

First, when the systems don't work, they light up your dash like a Christmas tree. That's how I know it recalibrates when you turn the wheel lock to lock. The car isn't at all silent when anything effects the auto braking or stability control. It lights and flashes everywhere. It won't let you use cruise control. It beeps at you. It says "ESC unavailable". Second, I have an obdeleven, and I can see that there are no errors in any systems, not that I'd expect there to be. Third, the traction control and stability control still kick in and work as intended. Lastly, something like this would definitely be in the owners manual. I've read it end to end.
I'm a bit of a computer nerd. The only thing you lose by disconnecting the battery is what is in RAM. You don't lose anything stored in ROM. All the important programming is stored in ROM. Only learned adaptions are stored in RAM. It would be incredibly poor planning if it were not done this way. Why would it save the radio settings, but lose its safety systems? That would be very poor design.
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[BSM]

You’re right, I just dreamt that all up. Those aren’t things that I’ve encountered on customers’ cars in real life. 🙄

 

[burgsprinta]

You’re right, I just dreamt that all up. Those aren’t things that I’ve encountered on customers’ cars in real life.

Who knows what those customers did or what kind of freak things happened? I'm sure they aren't all honest with you. I'm also sure strange stuff happens that causes calibrations to be lost. But it doesn't seem like changing or disconnecting your battery is the cause. Otherwise, every customer installing an aftermarket amp would be visiting you. I also know that some of the cars have to have the battery coded to them though,like the ones with auto start stop, so you can't just use any old battery to replace your old one. Some folks (maybe most) probably freak out when they reconnect the battery, and it says "Front Assist unavailable, emergency braking unavailable, adaptive cruise unavailable, esc unavailable, electric parking brake failure, blind spot monitoring unavailable", without realizing it'll go away once they just turn the wheel lock to lock, and turn the car back on. That's reason enough for many to bring the car in. All I can go by is my experience, same as you. No hard feelings.

Question, if some of the systems fail to calibrate in silence, what causes the customers to come in? How do they know something isn't quite right? Is it because of the warnings on the dash, or are they complaining about steering, esc, or the autonomous systems? Also, did any of these people turn on the car with the front assist sensor disconnected, because we've seen that does cause problems, as was alluded to above.


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[Laccos]

Can you give us a specific example of something like what you are referencing on a MK7 Jetta or Golf? Again, im not messing with you, im curious if there is potential risks associated that are not outlined in the manual at all. This is next level lets get the pitch forks out and put Volkswagen in the public spotlight again piss poor planning if what you say is true. This is recall level of what the hell were they thinking. /s

 

[BSM]

No, Mk7 VWs are actually pretty forgiving, like burgsprinta has been saying. I was making a general statement in response to Rabbitvw25’s hare-brained suggestion that disconnecting the battery would clear ADAS codes. You can’t clear codes that way anymore, it will just set codes in all sorts of systems for low voltage and lost communication. And there’s a chance you will mess something up.

 

[burgsprinta]

Op, we're so off topic it's getting absurd. Sorry! Do you know how your vw emblem fell off? Also, the sensor looks pretty dirty, from being uncovered. So maybe when vw replaces the emblem (hopefully under warranty), they'll either clean or replace your sensor. My '19 manual gli doesn't have acc (should have waited until model year 2021), but it does have the front assist, which I think uses the same or similar radar. A few times in bad ice storms, my front assist has stopped working, because it was blocked by ice and snow. Maybe your sensor is dirty, since it's naked.

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[jreed1337]

is there any reason why your car isn't under factory warranty still? if it just randomly fell off, tell your dealer that and they should replace it and correct the issue in good faith, or at least only charge you for parts. if there's no evidence of foul play, there should be no reason why it wouldn't get corrected under the factory warranty. they might push back, but using the right approach you should get it resolved under good faith.

 

[Rabbitvw25]

No, Mk7 VWs are actually pretty forgiving, like burgsprinta has been saying. I was making a general statement in response to Rabbitvw25’s hare-brained suggestion that disconnecting the battery would clear ADAS codes. You can’t clear codes that way anymore, it will just set codes in all sorts of systems for low voltage and lost communication. And there’s a chance you will mess something up.

So you never disconnected a battery on customers cars? What were the examples of any of the safety systems failing when you did it? It’s like saying all those people that jump start their dead batteries or swap batteries will die because a safety system would not light up and alert you to fix it? VW said screw this liability thing we’ll just turn the cars into unsafe junk every time someone unplugs the battery.
If all the acc sensor needs for it to work to have the cover to work, it wouldn’t hurt to disconnect the battery first, slap the cover on, reconnect the battery and either turn the wheel lock to lock or take it for a drive to reset the lights, like it was mentioned.

 

[dequardo]

Can you give us a specific example of something like what you are referencing on a MK7 Jetta or Golf? Again, im not messing with you, im curious if there is potential risks associated that are not outlined in the manual at all. This is next level lets get the pitch forks out and put Volkswagen in the public spotlight again piss poor planning if what you say is true. This is recall level of what the hell were they thinking.

Pump the brakes and lighten up Francis. Huge overreaction.

 

[Laccos]

Pump the brakes and lighten up Laccos. Huge overreaction.

Fixed your typo, my name is L-A-C-C-O-S.

OP, back on subject. Its in your best interest to try and attempt warranty work on this. If this were to happen to my car id certainly take this in for warranty work. They are also the only people who can work on this. Let us know what they say though because this is one of the most unlucky and odd posts i think ive seen yet.

 

[dequardo]

i assume you are young so the reference is lost on you. But yes back to the OP point. The emblem is simply plastic and cosmetic. Get it replaced and be sure to clean the sensor. Let us know how it goes.

 

[techlogik]

Well maybe after you read through all of the nonsense and childish crap on this thread you get to this post and see what needs to happen.

Long post but I'm going to retype my original story I posted about 10 months ago.

My grill was pulled off due to a fender bender and the bumper needed to be repaired. The body shop, being clueless like most with modern cars, took a screw driver to the ACC/radar mount behind the emblem to get it out, because it is wedged in there really well, you need some special tool to remove it without damaging the mount apparently. Which once it was all put back together again, it had a tiny 1mm wiggle in the sensor due to their lack of knowledge of what that sensor/mount is behind the emblem. Normally that sensor shouldn't be able to wiggle/move at all.

So what happened? That throws the alignment of the sensors entirely out of whack, you get ACC not available and has an error on the dash. You can't set the cruise and when you turn it on you get that error as well. Calibration errors in OBDEleven might show up, like mine did. But it might not throw an error either. It did every time on mine though.

EDIT: also left out after post below, anytime the bumper comes off or the grill, you are supposed to realign the sensors/wheels. Perform the process below.

The wheel alignment, the sensor behind the review mirror and the one behind the emblem are all interconnected and are required to be aligned and within spec.

The job cost around $400+ to complete. It takes like 3-4hrs according to the dealer because of all the things they need to align/check. Plus usually only one person knows how to do it there.

So, I ended up getting my body shop to pay for the first alignment/calibration, but 10min down the road, it went out again and threw errors over the first little bump.

The dealer diagnosed it and said the grill mount for that sensor you show a photo of was damaged. So, I bought a new grill online/OEM for 1/2 the price the dealer wanted.

Then paid them the labor to swap it out....after that, it didn't need another calibration, and started working without one. They said since they diagnosed the issue backwards/incorrectly, if the grill gets swapped and it throws an error, they would align it again for free. But they installed the grill/bumper and it just started working again. But I could tell, it wasn't like the original/factory calibration, the way it sensed cars/distance etc..was off...but it worked and was within spec.

Fast forward about 8 months....hit a few bumps and it was raining, not sure why rain affects these as well, assume sensor covered in water etc..mirror maybe? And guess what?!?! Went out of alignment again. Error message, ACC stopped/cruise quit while I was using it going down the road.

Took it to the dealer, they wanted to charge me $400+ stating the wheel alignment and sensors are out of alignment sometimes and just "normal maintenance" item. I said I don't think so. But go ahead and look at it and call me to let me know what the reason is it just stopped working. I don't hit potholes, I was literally just tooling along down the road over normal road little bumps, nothing unusual, and it threw the error out of nowhere. Anyway, alignment was fine, except they did tweak one wheels toe, then they called VW of US, maybe due to COVID, wanted more money or get paid, so they ended up getting VW to pay for it all, they checked alignment as stated, and also redid the calibration since none of the sensors had error/failure messages. Basically, there was no known reason for why it went out of alignment.

Moral of the story, as mentioned, you can put an emblem back on there, and recommend that before going to the dealer. Don't try to move/pry that sensor at all. But if the sensor wiggles at all to the slight touch like mine did, or you hit some bumps hard etc...wheels went out of alignment or whatever...it will throw those errors. ACC/cruise doesn't work...car drives fine. As mentioned earlier, take the bumper off/grill off....it needs an alignment stated by the dealer. But the only way to resolve this is take it to the dealer where some don't have that equipment. So call ahead, and usually their lead tech is the only guy who knows how to use the thing...and expect a $500 bill if your wheels/sensors are out of alignment. If a sensor goes bad, that is covered under warranty. But if it is wheel alignment issue, they will try to put you on the hook for the charge.

I made a post about last January/February if I recall of my entire ordeal...you can search for that. But I just gave most of that recount here again for easy reading.

Taking a battery connector off is a waste of time...trust me. This does nothing at all.

Also, even if OBDEleven shows an error, clearing won't fix anything, it will not clear, you have to take it to the dealer who has the proper equipment/diag tools to check the sensors and check the wheel alignment (that is a different error code if a sensor goes bad, covered under warranty and alignment as well).

Good luck....was a complete nightmare and terrible design and technology VW came up with. Maybe if it comes back within alignment and sensors check out either OK, or a sensor has failed, demand they escalate to VW of US and have them fix it for free because if there is no known reason/or a bad sensor, that is covered I was told.


So quick recap:

Wheels out of alignment, tires changed, bumper/grill removed: You likely are paying to have it fixed. Rock hit the emblem/knocked the sensor out of alignment....same.

Wheels aligned, sensor error/failure, or no known errors/reason why it is throwing the ACC error....they should cover/repair under warranty.

But only one way to know, it has to go to the dealer...go from there.