Dcc issues

[Greg_mk7]

Hello I have 2017 golf r with dcc. Since owning this car for the past 2 years ive been having this issue with the front suspension making a muffled clunking noise over speed bumps and pot holes at low speeds. The suspension also feels like it crashes over bumbs and generally feels unatural. My car was under warranty and throughout this time ive brought it in to have this issue checked out. After fighting with the dealership they replaced both my front shocks. The problem still persisted and they said it was a normal characteristic of the car. They checked all other suspension components and all seem good. Ive done the dcc calibration with OBDeleven with all four wheels in the air, but the suspension still feels horrible. There are no fault codes. Recently i tried unplugging the strutsand the ride is 100 times better and that annoying clunking noise is gone when they are unplugged. Is there anything else that can be causing this issue? The whole system needing to be reprogrammed? Im at a loss and am ready to just purchase a dcc delete and drive with the struts unplugged.
Any help would be appreciated.

 

[narsnail]

Strut mounts can be an issue on these cars, were they done when they did the front struts? I've personally never had good luck with Monroe dampers/struts on any vehicle I've owned, they don't seem particularly sturdy and never seem to last long. I do think the crashing over bumps is an issue with the stock setup; I'll be moving to the Bilstein B6 Damptronics with Eibach Springs down the road.

Do you have the pretoria 19s? Since you're in Montreal, I assume your roads suck too. May want to check if any of your wheels are bent or cracked just to be sure. Bent wheels can cause some really strange behavior in regards to handling.

I would find a good Euro shop and ask them to look into before you buy anything, but clearly there is something funny going on related to the DCC since your issue goes away when they are unplugged.

 

[Greg_mk7]

Strut mounts can be an issue on these cars, were they done when they did the front struts? I've personally never had good luck with Monroe dampers/struts on any vehicle I've owned, they don't seem particularly sturdy and never seem to last long. I do think the crashing over bumps is an issue with the stock setup; I'll be moving to the Bilstein B6 Damptronics with Eibach Springs down the road.

Do you have the pretoria 19s? Since you're in Montreal, I assume your roads suck too. May want to check if any of your wheels are bent or cracked just to be sure. Bent wheels can cause some really strange behavior in regards to handling.

I would find a good Euro shop and ask them to look into before you buy anything, but clearly there is something funny going on related to the DCC since your issue goes away when they are unplugged.

Strut mounts werent done when they replaced the struts, dealer said they were ok but I doubt they really checked.
I have the pretorias but it still does it with my 17 inch winter tires. The weird thing is that when i unplug my dcc struts that noise is completely gone and it drives way better.
I guess I could try throwing a new set of strut mounts on.

 

[krs]

Strut mounts werent done when they replaced the struts, dealer said they were ok but I doubt they really checked.
I have the pretorias but it still does it with my 17 inch winter tires. The weird thing is that when i unplug my dcc struts that noise is completely gone and it drives way better.
I guess I could try throwing a new set of strut mounts on.

Mounts and bearings if you do.

I have nothing to offer on the DCC issue. I thought the shocks did some fail safe setting if there was a failure.

 

[Cuzoe]

They do go into a fail-safe when unplugged. If your issue goes away when they are unplugged then the dealership needs to figure out what's wrong (assuming you still have warranty, or that they warranty their work). They are crazy if they want you to believe your DCC equipped car rides worse than one without DCC (which is essentially what you have with the struts unplugged). You've done the definitive part of troubleshooting for them... showing there's likely not a problem with the mounts or security of various hardware.

Does the car have the same behavior in every driving mode?... Comfort, Normal and Sport (or I guess Race in a Golf R)

Getting into the "weeds" of what could cause this...

• Failing front level sensor... I would check both but would be surprised if both were bad
  • I understand the calibration works, but really that only means the wheels hanging value is good.
  • You (or the dealer) could go to real time measuring values (or the equivalent in OBDEleven) for the level sensor, disconnect the control arm bolt then move the level sensor arm through it's full range, watching the values. I don't recall the full range but it should move smoothly through the values. I would expect a dead spot (value disappearing) would throw a fault but if the values jump around wildly at any point that's no good. And it may it may not persist long enough to cause a fault but could be causing the DCC module to "see" full/rapid compression and subsequently stiffening the damper.
• Failing or loose accelerometers... again easy to check both
  • These are located at the top of the strut towers, under the rain tray.
  • It's just one bolt holding them on and they weigh nothing so the torque value will be low... but you shouldn't be able to move them by hand.
  • If they are loose/failing you may get a similar problem to a faulty level sensor... DCC module "seeing" and reacting to movement that isn't actually happening.

The "programming" of the DCC module is through the dataset. There are different datasets for different cars (and for variants of the same car) to account for total weight, weight distribution, etc. But is very unlikely you have the wrong dataset loaded. The module gets coded with the VIN at the time of install (or replacement). If it gets installed in another car (or the module is new) the VIN mismatch causes it to dump whatever dataset is currently loaded and it will throw faults for needing to be programmed. A dealer would only be be able to program it with the proper dataset for your car. An owner could also load any dataset they want (including the wrong one) with ODIS-E... but extremely unlikely as there's nothing to gain.

 

[kyle251]

just wondering if you managed to get to the bottom of this?

my golf r wagon has the same issue. muffled clunk from front left going over small sharp bumps at low speeds. the noise is driving me nuts and caused me to replace every single component/bolts on the front end including new OEM shocks, bearings, hats etc.. noise is still there. funny thing is with DCC setting in comfort or if its raining the noise is mostly gone

 

[Greg_mk7]

Never did, i replced the strut mounts and bearing and endlinks and the noise was still there. Just like you when I put dcc in comfort mode the noise was less prevalent but still there, when I unplugged them the noise was completely gone. I got so fed up that I ended up buying non dcc oem golf r struts and a used dcc delete kit. Problem solved. I never liked dcc it never felt right, always felt odd and “artificial to me” You have three different damper rates for one spring rate so there is no way that that can be ideal.

 

[ZERO815]

In my experience w/ semi active damper (DCC) tuning in the OE world there might be 2 issues.
1. DCC shocks have a single external valve that controls rebound and compression damping. To work properly they need check valves to close whenever the direction of the shock movement changes. I have heard check valve noises on higher frequency (low amplitude) inputs before. Sometimes it sound like potatoes are bouncing in your trunk. For the OEM it’s a question of money to pay for quieter parts.
2. In a perfect world we have roads that are smooth as glass but have dips and crests. It’s the easiest request for the algorithm to control the body motion. Since the roads aren’t smooth as glass now you have a high frequency constant changing between rebound and compression motion paired with long wavy roads. The question is: How frequently does the algorithm react on the direction changes and what is the designed reaction? I have used a 4 poster with one of our single valve demo vehicles. It makes a hearable and visible difference if the algorithm goes through full soft on each direction change or if it „blends out“ the current . The pressure drop from controlled to full soft makes more noises than expected.

I guess w/ MK7 DCC cars it’s a combination of both. Unfortunately you can’t do anything about it. I don’t know if the APR/DSC controller uses a different control strategy.

 

[kyle251]

I tend to agree the DCC doesn't quite feel right. compared to my old mk7.5 hatch with no DCC which never had knocking or suspension issues. i may end up going your route later on and fit a set of non DCC struts. Running 19" rims with low profile tyres which im sure doesn't help either. oddly enough i
re-torqued the front left brake caliper bracket bolts and the noise is noticeably quieter. at least it seems that way anyway. it'll be interesting to hear some feedback on the APR controller if its as good as they claim.

 

[yakboyslim]

In my experience w/ semi active damper (DCC) tuning in the OE world there might be 2 issues.
1. DCC shocks have a single external valve that controls rebound and compression damping. To work properly they need check valves to close whenever the direction of the shock movement changes. I have heard check valve noises on higher frequency (low amplitude) inputs before. Sometimes it sound like potatoes are bouncing in your trunk. For the OEM it’s a question of money to pay for quieter parts.
2. In a perfect world we have roads that are smooth as glass but have dips and crests. It’s the easiest request for the algorithm to control the body motion. Since the roads aren’t smooth as glass now you have a high frequency constant changing between rebound and compression motion paired with long wavy roads. The question is: How frequently does the algorithm react on the direction changes and what is the designed reaction? I have used a 4 poster with one of our single valve demo vehicles. It makes a hearable and visible difference if the algorithm goes through full soft on each direction change or if it „blends out“ the current . The pressure drop from controlled to full soft makes more noises than expected.

I guess w/ MK7 DCC cars it’s a combination of both. Unfortunately you can’t do anything about it. I don’t know if the APR/DSC controller uses a different control strategy.

I know nothing about the OEM DCC control algorithms, but the DCC controller uses the wheel velocity (derived from the travel sensors) to determine rebound or compression (and damper speed) then chooses a positive or negative offset. This offset is then applied to the amperage damended by all the other inputs. The offset could be huge, but in the base maps and in good practice it is small (50 ma or so) So shouldn't be going through full soft as long as you don't have a wild set of damper settings.

 

[yakboyslim]

I tend to agree the DCC doesn't quite feel right. compared to my old mk7.5 hatch with no DCC which never had knocking or suspension issues. i may end up going your route later on and fit a set of non DCC struts. Running 19" rims with low profile tyres which im sure doesn't help either. oddly enough i
re-torqued the front left brake caliper bracket bolts and the noise is noticeably quieter. at least it seems that way anyway. it'll be interesting to hear some feedback on the APR controller if its as good as they claim.

The APR is identical to the DSC controller in every single way, so don't expect any new feedback over what people have said of the DSC. Even the APR base map is bit for bit identical to the DSC base map (except for the filename).

 

[ohtwo]

I found this thread because I'm trying to diagnose what's going on with the factory Monroe DCC dampers on the low-mileage 2019 GTI Rabbit I just bought. Everything about the car feels so solid, but driving over road imperfections feels like the suspension is from a 1985 Tercel. Noisy, jittery, and crushingly stiff regardless of drive mode. Surprisingly "comfort" is the worst setting. A passenger said it feels and sounds like the car has toilet plungers for shocks . I find it hard to believe it came from the factory like this.

 

[Cuzoe]

If you're able to put the car on a lift, or on jack stands, to get all four wheels hanging, you can do the DCC calibration. Assuming there are no system faults, which would probably throw up the little strut graphic on the dash, the calibration is where I would start. If the DCC model doesn't "know" the relative height of everything, you're going to get all sorts of weirdness, manifested as poor ride quality.

Incidentally, having all four wheels hanging also will let you have a good look at everything to make sure there's nothing obviously wrong from a visual stand point.

 

[ohtwo]

If you're able to put the car on a lift, or on jack stands, to get all four wheels hanging, you can do the DCC calibration. Assuming there are no system faults, which would probably throw up the little strut graphic on the dash, the calibration is where I would start. If the DCC model doesn't "know" the relative height of everything, you're going to get all sorts of weirdness, manifested as poor ride quality.

Incidentally, having all four wheels hanging also will let you have a good look at everything to make sure there's nothing obviously wrong from a visual stand point.

Thanks! Makes sense to do this before going too far down the rabbit (haha) hole. Assuming the calibration can be done with any of the common diagnostic tools?

 

[Cuzoe]

Yup, VCDS, OBD11, ODIS... all are capable. That calibration takes seconds, the longest part, unless you have a lift, is getting it on stands so four wheels are hanging free