Audi Hold Assist retrofit

[SunnyBard]

Over the course of the last week I've retrofitted the Audi Hold Assist to my car, it was one of the options I dismissed at time of ordering, thinking it would be of low benefit with an automatic. The fact that they call it "Hill Hold Assist" in the brochures does it down as a feature IMO, manually applying the electromechanical handbrake every time you stop soon gets tedious, meaning I've developed a tendency to sit with my foot on the brakes a lot of the time :Blush2:

Soon after I took delivery of the car I noticed that DavidB8 had a partial article on retrofitting it, but I decided to wait until I'd put the car through its first service before tinkering.

AudiEnthusiasts Hill Hold Assist Install (http://www.audienthusiasts.com/Project_HillHold.html)

A couple of other useful web sites

Audi Hill Hold Assist retrofit (almost) done - Audi A5 Forum & Audi S5 Forum (http://www.a5oc.com/forums/a5-performance-mods/17356-audi-hill-hold-assist.html)
Looking for crimp-on wire terminals for back of fuse block to add new circuit - AudiWorld Forums (http://forums.audiworld.com/showthread.php?t=2779750)

Getting the replacement switch and repair wires was easy enough (the fuse wire certainly not cheap though) just to confirm the latest superseded part numbers, I obtained the following

1x 8K2 927 225 C WEP (this is for RHD cars)
2x 000 979 009 E
1x 000 979 025 EC
1x 000 979 023 E

Plus a few extras such as wire, fuse, sleeving/fleece tape, heatshrink tubing.

I scoured the web for articles explaining suitable routes for the extra wires, this article is actually about fitting a radar jammer, but illustrates the ECU box route (albeit on a LHD car) which I used.

DIY: Install a Laser Jammer - AudiWorld Forums (http://forums.audiworld.com/showthread.php?t=2795909)

To keep things neat I decided to run the extra wires within braided "fishnet" sleeving from the centre console to the right hand front fusebox where I picked up power from a spare fuse position (I couldn't face taking power from the rear fusebox like the true factory fit) then up through the ECU box, within the trough under the windscreen cowl (past the brake servo, battery terminals and washer bottle) down to the ABS controller.

Removing the ABS plug is simply a case of sliding down the red lock and rotating the grey lever, but then there's very little slack to play with and I was a bit stumped how to open up the connector to insert the extra contacts, I found a semi-helpful German article, but still couldn't figure it out (not wanting to break anything) so put it back and left it for a few days.

http://www.audi4ever.com/forumv2/index.php/topic,63316.0.html

Eventually I found a Spanish article with photos that really helped with the ABS plug, again the author warned about breaking the plug, you need to register to see the photos.

Brico instalación de Audi Hill Hold Assist - Electricidad Audi A4 B8 - Audisport Iberica (http://www.audisport-iberica.com/foro/index.php?/topic/284439-brico-instalacion-de-audi-hill-hold-assist/)

Now I felt I knew enough now to proceed, and cut the tie-wrap holding the ABS wires in place, the top tab of the hood popped off easily by inserting and twisting a Stanley blade, after pulling the top of the hood forward a few mm, I could insert a tie-wrap in one side and out the other to form a handle with which to pull the hood, while inserting a finger into the bottom of the hood and levering it left and right to remove the tabs on the sides towards the bottom ... I got it off without breaking them.

Then using a pin I piggled out the rubber bungs from the holes for pin8 and pin16 (double checking the numbering) at this point looking into the holes, it became clear what the comment about the purple retaining plate meant, and I levered the two purple lugs towards the centre of the connector, this opened the holes and the repair wire contacts clicked home nicely, and I levered the retaining clips back.

The pins on the repair wires came with rubber plugs included to make a good seal into the connector

Yesterday I was ready to solder the repair wires at the switch/fuse/abs locations to my extra wires, I used heatshrink tubing on all the soldered joints and self-amalgamating tape for good measure over the joints to the ABS unit, and used fleece-tape to bind the repair wires onto the loom more neatly ... no local dealers/car parts/car audio places seem to stock it, but you can get it from eBay.

Doing the re-coding was the easy bit, with this and enabling TPMS, my VCDS has partly earned its keep.

Overall it took a bit longer than I hoped it would do, mainly due to my unfamiliarity with modern cars, lack of room for sausagy fingers, the components of the car being designed to clip and snap together easily but only come apart with difficulty. Respect to anyone stopping to take photos and write a full how-to article, it would have slowed me down too much, but I'm happy to answer questions if anyone finds this in future and has any doubts.

Finally it's so nice to see the green (P) light up when coming to a halt now, it's noticeably smoother setting off again with the AHA compared to the electromechanical brake, no more squatting down of the car due to only using the rear brakes. I can see it's going to take me a couple of weeks to remember I have it, all-in-all I'm very happy with the retrofit :D

[Guest 2]

Good job - thanks for writing up ;)

[ScottyUK]

Good write up. I'd love to know if it works on a Stop/Start car.... and if so why didn't they allow it when I ordered my MY2010 :(

[Zenerdiode]

It was either on the 'configurator' or I've read it in my manual; that Hill Hold Assist and Stop/Start can't co-exist. That's from the factory, mind, so I don't know if they'll function together if we activate with VCDS.

[ru55]

Before embarking on this I think you need to check that you have right version of the ABS module installed on your car. Hill hold was missed off my car when being built and I have been assured that it is IMPOSSIBLE to retro fit. My own research indicated it was the ABS module that was the issue but happy to be proved wrong.

[SunnyBard]

Before embarking on this I think you need to check that you have right version of the ABS module installed on your car. Hill hold was missed off my car when being built and I have been assured that it is IMPOSSIBLE to retro fit. My own research indicated it was the ABS module that was the issue but happy to be proved wrong.

I presume you checked the build codes (on the sticker in your logbook) and found it wasn't a 1AT module?

Did you extract suitable recompense from them for the mistake?

[warp_speed]

What do you think of the Auto Hold Assist, I retrofitted it to my S4 but found a worrying noise whenever I'm parking the car with it activated, like a vibration coming from the brake pedal. I think its due to the stop go when your parking a car. I guess I just need to deactivate it when parking. Do you have this issue? I've got an Automatic so unsure if this is what the issue is.

[SunnyBard]

I still love the Hill Hold, can't see why they don't make it standard equipment. No noises or vibrations when parking with it, the only noise I hear is when starting off again a little "ting" noise which I assume is the brake cylinder recharging, same as you sometimes hear when the "brake disc wiping" is happening.

My car doesn't have stop/go, when I had a manual A6 for a few days while mine was in the garage, I did find that the stop/go and the hill hold kind of competed with each other, maybe I didn't have long enough to get used to the combination with a manual gearbox.

I have a little issue developing which I think is the S-tronic needing recalibrating, it seems to be biting just a little to hard on the clutch when stationary, sometimes if I've come to a very gentle stop, so the hill hold is only keeping the brakes gently applied, rather than firmly applied, the car will creep forward against the hold, as soon as it moves an inch or two the hill hold does notice and more firmly applies the brake with a bit of a jolt.

I keep meaning to research performing a recalibration of the DSG, but i'm not convinced the instructions on the vagcom site exactly match my part numbers, so have held off for now.

[mhurer]

I use it all the time and for the £75 extra I can't believe it is not standard now. My wife recently ordered her A4 and I made sure she included it in the order - the car has auto stop-start and i've had no issues using both at the same time. There was a short period of time when auto stop-start was first introduced when the audi configurator would not allow you to add the hold assist, but they soon sorted that out - perhaps teething problems with the combined technology.

[hman_01]

Going to order this up - my wife has it in her car and.....managed to forget to apply the brake on mine because she is so used to it happening on hers - car rolled down the drive into the house !!!

[ziggycol]

I like the Hold Assist and use it all the time but do tend to switch it off when low speed parking etc. when shuffling between forward and reverse just because it is smoother in those circumstances with it off.

[chrishamer]

As long as you remember to turn it on every journey. I really dislike the fact that the system doesn't auto-engage - like it does on Merc's for instance.
You have to have the engine on and seat belt fastened before it activates by the push of a button.

Once on though the system is great, as long as you aren't parking or maneuvering at low speed.

[PerryGarrod]

Hi
I'm attempting to complete the hill assist retrofit. Have got all the bits but am struggling at first step. Can't get the original break switch out. What screws hold it in? I cant see them and despite various attempts, cant get any bit on phillips or flat head
What's the secret?
Thanks
Perry

[SunnyBard]

Have you removed the whole of the black trim from the centre console surrounding the gear shift?

I used a set of trim removal tools (https://www.amazon.co.uk/dp/B004OEL4LW) to slowly squeeze in and release it all round from the aluminium (I guess other cars can have different material inlays etc) then I think the switch unclips from underneath once you have the plastic surround free. I know I still have my original switch somewhere and tried to find it to remind me how it goes, but couldn't find it, can you see how it clips/unclips by looking at your new switch?

[PerryGarrod]

Hi, yes, everything out and accessible, but something is definately holding the switch in.
I've removed the cable, and temporarily connected to the new, replacement switch.
When I unclip the side clips holding the switch in, it does come out a couple of mm but definately being held by to the "front".
I guess I might have "burred" the screws, is which case I have a big problem.
Looking at the replacement, I cant see what the two screws do to hold the swich in? THey are certainly not visible from the bottom of the switch housing

ANy advise welcomed....otherwise I enter the realms for drill and brute force.

Perry

[SunnyBard]

Any advise welcomed....otherwise I enter the realms for drill and brute force.

If you can post some photos, it might jog my brain (it was 4+ years ago)

[PerryGarrod]

What is your email so I can send photos. Mine is name at hotmail dot com

[PerryGarrod]

Was it a Torx screw or flat head or philips screw head?

[PerryGarrod]

Have seen David@audienthusiasts.com photos but didn't help me. Have tried emailing him but he has removed his contact email page so not sure he's got my email as he's not publishing his address because of rubbish emails being sent to it. Will let you know how I get on once I've cracked it.....hopefully not literally

[PerryGarrod]

Got the switch out after all the messing around. Once out reveals switch not held in with any screws, just the clips, so just needed big push. Don't know if that's a mod of 2013+ or were just missed off my vehicle. Thanks for all help. Onward and upward.

[PerryGarrod]

Hi all.
Just a quick update for all looking at performing this retro fit.
for the parts, as specified on David @ AudiEnthusiasts, highly recommend contacting Mickael at mshugaev-2008 (http://www.ebay.co.uk/usr/mshugaev-2008?_trksid=p2057872.m2749.l2754). Got everything I needed, terminals, cables etc., and therefore no need to splice cables.
Also, for RHD Audi's anyway, would offer the following, by way of "lessons learnt"
1. The existing hand brake switch was not held in by any screws, so just needed a good push to remove. Dont know if this is a revision or whehter they simply did not install when mine was build. COnsequently have just let the "clips" secure the new switch, as before. Wasted some time on this one....looking for screws that were simply not there.
2. I'm running my cables to the Fuse Block on the passenger side (as the ABS unit is on this side so figure it'll be tidier to run the cables when I complete the job.....waiting not for disc pad replacement when I'll take the wheel housing off and run the wires via that route. Fingers crossed!
3. When trying to get the Black Fuse block off, struggled with this. Reason being it's tight up to a bulk head, and didnt appreciate for some time that the clip holding it in place is NOT on the bottom, but on the top of the block, which is hidden by the bulk head. Once I realised this, it did come off quite easily, blind/touch and feel so to speak. HOWEVER,
4. Had to remove the Glove Box as could not get access to the rear of the block with it in place. This came away really easily, held in situ by 6 bold, 3 inside and external 2 bottom and 1 side (in the fuse area. Once dropped, then came the next issue/challenge - as up to know it was all "new".
5. Had to take a spur off an existing live feed, which, when you look at the rear, are all on the left. I bottled it at this point and took the vehicle an auto electrician, who kindly did the spur & soldering into one of the (many) available free slots. Thanks Auto Electric Jersey (Channel Islands). That took the chap a few minutes and job done.
6. Connected the new wire from the new switch, and for the time being put the car back together, as I said previously, now waiting for the service when will complete the install.

Hope this is of use to any other keen DIY'er

Tried contacting David at Audienthusiasts but he's removed his contact screen to if anyone can forward this into onto hi, which might end up on his web page in due course, that would be great.

All the best & thanks
Perry

[sanstorm999]

I thought I would mention I have completed this retrofit and all works as it should except on earlier vehicles MY2013 A5, when you remove your foot from the brake pedal the engine starts (start/stop deactivated) because the monitoring of start/stop is via the brake pedal not the throttle pedal - disappointing really!

[jp_paul]

Just finished this retrofit on my late08MY A5Q with 1AT ABS. Works a treat.
Thanks for the tips on earlier posts.

One thing that caught me out was how far the ABS plug pin release (purple bit) moves. Only needed to slide it a few mm using a lever on the end with a tab in the middle. I was trying to get it further for ages, but there was no need.
I routed cable through the ECU port, then alongside main ECU cable, through the big rubber grommet. Then passed through the engine bay bulkhead where a big cable comes through from the cavity, again through a big rubber grommet alongside the cable. Well neat.
Took power feed from black fuse section in driver's doorway. then ran the cables together over the footwell air vent and alongside the centre console trim.

Amazed this wasn't spec'd by the original owner. Why on earth not for the few quid it would've cost?!
I had to have it as my Passat wagon has it, and once you're used to it, it's hard to live without.

[SunnyBard]

Just finished this retrofit on my late08MY A5Q with 1AT ABS. Works a treat.

glad you got it done, yes the ABS cap was a bit worrying at the time


Amazed this wasn't spec'd by the original owner. Why on earth not for the few quid it would've cost?!

Think it's standard now, but at the time I specced mine, I didn't think hill hold would be much use with an automatic, so didn't order it.

[jp_paul]

I didn't think hill hold would be much use with an automatic, so didn't order it.

Totally understand that. I guess it's a bit like the stop/start - kind of makes AHHA pointless.

I've never been brave enough to have another auto since my 190e chucked me into a ditch (not that a tip or s-tronic quattro would do that!)
I bought my manual A5q for nearly as much as a mate spent on a new mechatronic unit in his S5 stronic - I can't afford repair bills like that!

[SunnyBard]

I guess it's a bit like the stop/start - kind of makes AHHA pointless.
I bought my manual A5q for nearly as much as a mate spent on a new mechatronic unit in his S5 stronic

I got rid of my A4 as I suspected the mechatronics was on the way out (hydraulics overtemperature according to vcds)
now have an A5, still auto, but with both start-stop and hill-hold from the factory, they don't fight each other, though the start-stop is sometimes a bit unpredctable.