4-channel Bosch 5 ABS with EDL to Coupe

[A1QSHIP]

OK, as if I do not have enough to figure out on my Ersatz S2 project. I am wanting to use the 4-channel ABS system with EDL from a North America 1995.5 S6 & install it in to my Coupe20v. The S6 ABS has some basic traction control features that the repair manual states works on both front & rear axles. On my S6, when coupled with a V8 torsen rear diff that I have installed, this has proven to be an effective & unobtrusive E-differential system.
I will be using the S6 brake master cylinder for starters & may use a brake proportioning valve/s if needed. The Coupe has already been fitted with BoxsterS calipers both front & rear with 323/300mm rotors.
I have been studying the wiring schematics, Electrical Troubleshooting Manuals, & now need more information. Here in the States we did not get the automatic transmission with the turbocharged 20v 5-cylinder.
Looking for function/description information as to what input the automatic transmission input shown in the ETMs has on the ABS system. My intention is to know if there is any possible way to "tune" the ABS via the transmission inputs.
Also, in the S6 ETM for the instrument cluster a TC lamp, traction control lamp is shown. Can anyone elaborate on this feature? What color wire may go there & where does it come from?
Yes, I would like to have a couple of LSDs for the front & rear diffs but this is cheaper.
I figure if Walter Rohrl says he is faster with traction control & ABS & that it is banned in F1 then it must be effective.
TIA, Chris

[UrS4boy]

Good luck. Way WAY too much work for marginal benifits. Plus you lose the ability to effectively use the rear diff lock.

I agree that on a C4 96 (95.5 in the US) or 97 UrS6 adding a V8 Torsen to EDL is a benefit. But to try to put EDL into a coupe with existing ABS and locking rear diff is a massive waste of time and effort, in my opinion.

BUT hey, good luck.

[A1QSHIP]

Rear diff lock has already been deleted as a Torsen has been fitted to the rear differential. On the S6 the EDL & rear torsen has proven its worth on the racetrack in low traction corner out situations i.e. no inner wheel spin. Control module fits in place of original, wheel speed sensors appear to be plug-& pray. Harness is definitely long enough. Having a complete harness simplifies matters. ABS pump bolts in place of the original & only an additional hydraulic line needs to be run. Lines are being replaced anyway. Interior is out for engine, automatic climate control harness, ABY battery box installation. ABS delete switch will be incorporated, easy enough. Easy Peasy.
Chris

[A1QSHIP]

Anyone have electrical schematics for C4 chassis cars sold in Europe? I have a full set of Bentley Manuals for the North American versions but no help with what I want to find out. Inquiring minds want to know.
TIA, Chris

[domas]

elsawin has schematics for 1997 C4, can supply

elaw on motorgeek has done the conversion

[A1QSHIP]

I saw where he was doing the conversion for his project. I need the euro C4 schematics for the instrument cluster.
Thanks, Chris

[domas]

can still supply schematics.
but you have not told me what is it exactly you need.
all details of the car, engine, year, etc - may be important, may be not important, just want to make sure. I can only supply C4 1997 schematics from elsawin, but i can find older elsewhere.
There may be difference from Audi 100/C4 to Audi A6/C4

[Horsty]

interesting project.
I'm testing the mk20 abs (golf3, passat)...

[A1QSHIP]

I will post a picture up later this evening.
Thanks, Chris

[elaw]

I've done it (okay not on a coupe but on a B3 sedan), it's not insanely hard, and you do NOT have to lose the rear diff lock functionality!

The electrical hookup becomes a hybrid of the B3 and C4 ABS system. You mostly use the C4 harness, but keep the ABS switch, control relay, and connections to the diff lock system from the B3. What you end up with is a setup that depowers the ABS (/EDL) ECU when you lock the diff or press the button to disable the ABS.

Some difficult parts when I did mine:
* Getting the harness through the hole in the firewall. I depinned the pump connector, fed the cable through the hole, then put the pins back in the connector housing afterward.

* Mounting the ABS pump/valve unit. My car did not originally come with ABS but even if it had, the pump is dimensionally completely different. So I had to fabricate a rather complex bracket to support it.

* This one drove me nuts until I realized what was going on: the ABS warning light indicator output from the ECU is designed to interface to a computer and not a light bulb, and as a result its logic is inverted. If you just wire it to the bulb in the cluster, the light will be on when it's supposed to be off and vice-versa. I had to build a little inverter circuit to fix that.

You can read about what I did in my build thread on MG: http://www.motorgeek.com/viewtopic.p...2240&start=775 starting near the bottom of the page.

I think I've got a spreadsheet around somewhere that shows the interconnections between the C4 and B3 ABS harnesses - I'll try to remember to upload it tomorrow. If I forget, shoot me a PM.

[elaw]

interesting project.
I'm testing the mk20 abs (golf3, passat)...

I'd be interested to see how that works out! I actually started down that path... in some respects it's much simpler than retrofitting the C4 ABS because the ECU is built into the pump unit (assuming I'm thinking of the right ABS unit). What stopped me is that I got the sense it expected to communicate with the engine ECU via canbus which wouldn't be doable in my car.

[Horsty]

I'd be interested to see how that works out! I actually started down that path... in some respects it's much simpler than retrofitting the C4 ABS because the ECU is built into the pump unit (assuming I'm thinking of the right ABS unit). What stopped me is that I got the sense it expected to communicate with the engine ECU via canbus which wouldn't be doable in my car.

i use the mk20 without canbus. therefore it's not going to communicate with anything.
for my 7a quattro i coded it to passat vr6 syncro.
but in my case it will still take a while till i'll install it.

[A1QSHIP]

Page shot of S6A6 Instrument Cluster Circuit

This is what I am looking for. Information regarding K86 lamp & T26/5 connection. Searching the workshop manual did not provide any answers. I am wondering if there are any European Market C4 chassis, 1995.5 until end of production that would have a "Traction Control' feature. The instrument cluster circuit board in my S6 is from a RHD A6 with trip computer so I know that the bulb & circuitry is there.

Looking thru the wiring diagrams leads me to believe that at least in North American vehicles this version of ABS is used on both S6/A6 manual & automatic equipped vehicles from 1995.5 thru 1997. I am curious as to the inputs the automatic transmission has to the ABS unit. Hope I do not have to buy a whole car to figure it out.

@ elaw; I have read thru your post & found it informative. Thank you very much. Good to know about the ABS malfunction lamp operation. Two more things. The bracket to mount the ABS hydraulic will come from a B4 chassis vehicle. On my S6, the orange connector Tao/1-6 & the brown connector T6bf/1-6 are there but are not connected to anything.
Chris

[UrS4boy]

1997_Audi_A6_System_Wiring_Diagrams

I think you will find what you need on pages 4/48, 25/48 and 45/48 of this:

http://12v.org/urs/1997_Audi_A6_System_Wiring_Diagrams.pdf

[elaw]

Attached is some info that may help. There's a spreadsheet showing (rather cryptically) what connects to what, a wiring diagram that's the closest I could find to the UrS6, and some notes about the UrS6 ABS harness.