Sci-fi_Wasabi

Hi, I have a 2009 A8L with the grill below and Adaptive Cruise Control. On occasion it would give an error, but after getting a carwash a month ago, it consistently says ACC Not available!, which is different than the ACC Blocked which would indicate misalignment. Reseting the error code with VCDS did not help.
Below is the VCDS error code I get, and the some measuring blocks when parked.
I was hoping someone could help me with a few things:

1. I can’t seem to get the little grill cover off the radar emitter to check the device and wiring. I see a little slot, indicated with a blue arrow, but I’ve tried sliding flat metal probes in there an pulling, but no luck getting getting it off. Any idea how to pull it off. I’d prefer to not pull of the whole bumper because of weak bumper tabs.
2. Does anyone know where the wires connecting to the radar route to (like towards the drivers side(U.S.A.) or passenger side behind of the bumper).
3. If I get a used radar module, would it require component protection removal.
4. Any other suggestions figuring out what is wrong with this thing.

Thanks.

VCDS LOG:
Address 13: Auto Dist. Reg Labels: None
Control Module Part Number: 4E0 910 561 F HW: 4E0 907 561 F
Component and/or Version: ABSTANDSREGELUNGH03 0020

Software Coding: 0011218
Work Shop Code: WSC 02313 785 00200
VCID: 254B5039ECC0856C74-8070

1 Fault Found:
00003 - Control Module
014 - Defective - Intermittent - MIL ON
Freeze Frame:
Fault Status: 10111110
Fault Priority: 5
Fault Frequency: 3
Reset counter: 78
Mileage: 222052 km
Time Indication: 0
Date: 2019.03.02
Time: 15:56:00

Freeze Frame:
Temperature: 13.0∞C
Voltage: 13.57 V
Bin. Bits: 00100000

haggisuk

Hello. I am replying here rather then to the email you sent me so it may help others if it does find the answer.

I suspect from your detailed info that the sensor or cabling attached to it has got water ingress.

for access to the front of sensor I found it easier to remove the trim from above the sensor first. That's the one where the number plate would normally be.

access to the whole sensor and wiring require bumper off but please note it's not a difficult job and I have done it on my own a few times.

Your harness will run from passenger bulkhead forward to the bumper and along the front from the passenger side.

sensor replacement won't bring on component protection and is attached by a few bolts in behind the steel reinforced bar that can only be accessed with the bumper cover off the car.

have a look here for further tips and info on how to calibrate the sensor yourself if you do indeed fit a new sensor.

http://forum.a8parts.co.uk/showthread.php?t=10419

Sci-fi_Wasabi

Thanks, Haggisuk,
it is at least reassuring that I should not have to deal with component protection if i replace the sensor. I'll take the license plate trim off again to look for any further access to the ACC cover. I'll probably wait for warmer weather to take the front bumper off.
So given that Group 2 and Group 11 of the measuring blocks are working, would that suggest that the module is partially functional, and just one aspect of the emitter is not... thus maybe 1 wire is out that carries that Group 1 signal? Also, when you say the wiring comes from the passenger side bulkhead, do you mean the UK passenger side, or the USA passenger side?
Thanks for the help again.

haggisuk

the wiring always comes from passenger side regardless of country.

the radar module talks over canbus to the rest of the car and because of that I'd say the wiring is likely to be ok.

the module seems like it got water inside and killed the radar part leaving the comms side of it ok

of course that's just my gut feeling and may well be incorrect. If you can get another radar at sensible money I'd get it so u you have it on hand before getting the bumper off.

you can always sell it again if you find something else.

Sci-fi_Wasabi

thanks, good ideas. I will look into all of that.

Sci-fi_Wasabi

Just to help anyone trying to take a look at their ACC radar who has a 2009 grill like mine.

1st remove the license plate cover or delete: remove 4 phillips screw are along bottom edge, then hinge out wards. The top of the cover has these 5 plastic hooks behind them as seen in the picture, so have had to wiggle and angle the plate upwards till it unlatches.

There are 2 holes above the ACC cover, stick 2 screw drivers in them and simultaneously push the ACC over retention clips forward.

Here is a picture of what the clips look like.

My ACC radar and cover are dirty inside as the picture shows, so i cleaned them up.

Unfortunately cleaning them and wiggle wires around did not help resolve my "ACC not available" issue.

You can’t take the ACC out or unplug it or do much to it with just the little cover off, you need the bumper off for that. Access to the horizontal and Vertical adjustment screw seems a bit difficult too with just the cover off. Maybe you can get the to the horizontal adjustment screw through the top left hole that you put the screw driver through to take off the cover, but even then it would not be a directly straight shot as it is a bit lower than the hole.

Hope that helps someone in the future as more people have problems with this feature.

part numbers for the ACC cover pictured: 4E0854511AA

license plate delete part number as pictured: 4e0807287AM

Sci-fi_Wasabi

To continue what I was doing with the ACC repair.

1st of all I was learning as I was working on the ACC. To start, for anyone having issues with the system, whether it is Blocked sensor, misaligned, etc (so long as you did not bend the bracket or damage the thing). I would start by resetting the ACC by going to the VCDS Basic Setting menu and doing the on/off reset to field 1,2,3, and 4 as described by HaggisUK/Delboy in his most excellent ACC retrofit post

Adaptive Cruise Control Retrofit - A8 Parts Forum

After that get on a highway, find a car to follow, and turn on the ACC so it can relearn stuff. Do this for a couple days, and it may sort itself out.

I did not learn how to do this resetting until I replaced the ACC with another one, so maybe my old one was just fine (physically it was in good condition), and could have just used a reset. I think the system is somewhat forgiving if the alignment is off a bit, as it seem to lock onto things and follow rather then just blindly accept what ever crosses in front of it.

To start, take the bumper cover off.

Getting the harness connector off of the ACC is a but tough given the space between it and the A/C condenser. I could not do it via the usual Audi "pinch tabs, push in and pull out" method. Also, your tabs may break.

Here are some pics of the connector so you know what you are dealing with.









To get the connector off while the unit was installed I had to use a pick to push the tab on one side out. While the tab was bent out, I was able to slip a thin screw driver between the unit and the connector to lever it back. There is a metal protrusion in the way, so you need a thin screw driver that can just get into the space as shown. Do this for one side just enough to get the connector tab off of the notch it secures too. Then do the other side and and alternate sides to lever the connector off. You will have to do some of it by feel as one arm is above the bumper and the other below the bumper.







My old ACC was pretty well aligned when it was working.
So I matched up its alignment to the new one.

I secured both next to each other on a 2x4 as it would be secure on the bumper (using 3 screws and washers, nice and tight) (my pic is not my actual setup, just demonstrating what i did. I used a small bubble level to get the new one’s level in the x and y axises to match up to the old one, while adjusting the horizontal and vertical adjustment screws. ( this requires a small Allen wrench, I don’t know the size, just used what fit from my box-o-wrenches…). Make sure your bubble level is in the same spot on the back of the unit to which you mirror bubble measurements, as sliding it to the left or right or up or down makes it change.






I reattached the new ACC to the bumper. you can only check vertical level here, but it actually was pretty spot on for where the vertical level was on my old one.






I turned the car on, and checked the thing. It threw some error codes still, but I also realized my battery voltage had gone down a bit as the car sat around a few days for disassembly. After running the car a bit to get more juice into the battery, the communication of the ACC with the car was fine.

I reset fields 1-4 with Basic setting as described. I got an error that said “personal identification” missing or something. It tuned out that the ACC was looking for the Engine Start finger print scanner which my 2009 A8 does not have, but the 2008 A8 the unit came from did have.

I changed the last digit of the software coding from 0011214 to 8 (0011218) which was my original coding and it was then fine for my car setup

I put everything back together.

I got on the highway, followed a car and turned the ACC on. Did this for a couple days, so it could learn.

It seems to be somewhat forgiving as I did not need to make any manual adjustments, and it works as fine as i need it to… maybe it could be better on following cars during more acute curves on the highway… but i can’t really recall how it did before… think it is about the same.

My old Group 2 measuring block was -.0111 on the old unit, it is -.222 on the new.

My group 11 Angle was .833, now it reads like 2. something, and the turn rate change from .11 to now .10.

I don’t know what all these numbers mean really, but it is all good now, and no component protection has kicked in over the 5 days it has been installed.
Now i just need to see if it wiggs out after a car was to see if connections/wires are all good.
Hope this helps someone else.