sport diff retrofit help. knowledge building

[wrxkyle]

so i'm feeling like possibly swapping in a sport diff. almost every reply i have seen has been that it isn't doable but i am having a hard time understanding why not.

you'd need a complete setup with module and harness sure, but vagcom has the coding to enable/disable sport diff so i assume you could just turn it on with vagcom right?

anyone know what the twisted pair wires on this harness are?

https://www.ebay.com/itm/2010-AUDI-S...cAAOSwrD9d3CHo

looks like power, i assume canbus communication is one set of wires, and maybe a sensor or something is the other set of wires? the large white and brown i'm going to assume are power for the pump and solenoids motor or whatever magic motor/pump/solenoid these use.

[Audi 4 Life]

Its def possible, Need the axles too i believe. And if your not manual then you need more cuz they are diff drive shafts. Also their are two different drive shafts for manual as well for torsen and crown diff.

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[zaxophne]

Well I didn't mean to post in this thread(Edited)

[wrxkyle]

thanks that's new info i'll add to the list, it is a dsg so i guess different drive shafts.

[Audi 4 Life]

thanks that's new info i'll add to the list, it is a dsg so i guess different drive shafts.

And rear axles

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[MagoAmado]

I've been working on fishing the Sport Diff wiring out of a harness. I don't have pictures of the full sport diff wiring bits but here what I do have. I'll update this post as I make more progress and take more pictures!

Wiring wise its not super complicated if you get a full enough harness. The crucial part is going to be getting wiring up to the fuse box. Past that its just a couple of CAN bus wires. For the sport diff part at least.

Trunk area wires:

White/Red - Power (Fuse 9 in carrier 2)
Brown - Ground
Black - Positive connection in main harness (Can be traced by following wire from fuse 12 in carrier 4)
Orange/Blue - CAN bus high
Orange/Brown - CAN bus low

Kick panel wires:

These go to active steering (module J792) if installed. If active steering is installed, adding the sport diff should end at splicing the CAN wires in at the kick panel as long as the connection point is the same on those vehicles. If not, the ESP sensor units have to be installed as well.

Orange/White - CAN bus high
Orange/brown - CAN bus low

If you don't get a full enough harness to differentiate the two orange/brown wires by length you can track them down from the diff ecu. The kick panel wire is pin 41 and the trunk wire is pin 37.

ESP Sensor units:

Brown - Ground
Orange/White - CAN bus high
Orange/brown - CAN bus low
Black/Violet - ABS Module (Pin 32 in ABS connector)

This is the course that the sport diff wiring takes. Most of the wires only go the length of the red area. The yellow is the path of the two CAN bus wires going to the driverside kick panel. The green path is where the ESP sensor units are installed under the seat and their wiring path. The blue is where one of the wires for the G sensors goes to the ABS module in the engine bay.



The green in this one is where the two CAN wires splice into the harness just before the parking brake module. The violet is where the black cable gets spliced into the harness.



This is the CAN splicing on its own.



This is where the power cable goes into the fuse carrier.



This is where the CAN bus connects in the kick panel and the major ground connection is where the ESP sensor units ground wire is spliced in.



Bonus pic of how the CAN connections are spliced together.

[zgastin]

I've been working on fishing the Sport Diff wiring out of a harness. I don't have pictures of the full sport diff wiring bits but here what I do have. I'll update this post as I make more progress and take more pictures!

Wiring wise its not super complicated if you get a full enough harness. The crucial part is going to be getting wiring up to the fuse box. Past that its just a couple of CAN bus wires. For the sport diff part at least.

Trunk area wires:

White/Red - Power (Fuse 9 in carrier 2)
Brown - Ground
Black - Positive connection in main harness (Can be traced by following wire from fuse 12 in carrier 4)
Orange/Blue - CAN bus high
Orange/Brown - CAN bus low

Kick panel wires:

These go to active steering (module J792) if installed. If active steering is installed, adding the sport diff should end at splicing the CAN wires in at the kick panel as long as the connection point is the same on those vehicles. If not, the ESP sensor units have to be installed as well.

Orange/White - CAN bus high
Orange/brown - CAN bus low

If you don't get a full enough harness to differentiate the two orange/brown wires by length you can track them down from the diff ecu. The kick panel wire is pin 41 and the trunk wire is pin 37.

ESP Sensor units:

Brown - Ground
Orange/White - CAN bus high
Orange/brown - CAN bus low
Black/Violet - ABS Module (Pin 32 in ABS connector)

This is the course that the sport diff wiring takes. Most of the wires only go the length of the red area. The yellow is the path of the two CAN bus wires going to the driverside kick panel. The green path is where the ESP sensor units are installed under the seat and their wiring path. The blue is where one of the wires for the G sensors goes to the ABS module in the engine bay.



The green in this one is where the two CAN wires splice into the harness just before the parking brake module. The violet is where the black cable gets spliced into the harness.



This is the CAN splicing on its own.



This is where the power cable goes into the fuse carrier.



This is where the CAN bus connects in the kick panel and the major ground connection is where the ESP sensor units ground wire is spliced in.



Bonus pic of how the CAN connections are spliced together.

I posted in the other thread but I am working on tearing down an s4 to swap into my avant. Let me know if you need help figuring out where anything goes since I have the full car.
Do you only have one esp sensor in the a4? Here are the two from the s4 in case you need part numbers. received_547436982773152.jpeg

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[wrxkyle]

this is amazing info thanks. i think soon we'll be able to decrypt exactly what needs swapped, so are there extra esp sensors related to the sport diff or are those in every s4 as part of the traction control system? i'm guessing can wiring is not resistance critical as it is just data connections and i wonder if they could be spliced into the canbus wiring anywhere, like in the trunk. not exactly sure how canbus works itself. is it just a data highway with free on/off access at any point?

[S4'ed]

You can splice into the CAN bus anywhere, location is not critical, as long as you find the correct CAN bus, there may be several separate CAN busses (Powertrain CAN, Infotainment CAN, Comfort Systems CAN...)....not sure about the S4.

[MagoAmado]

I posted in the other thread but I am working on tearing down an s4 to swap into my avant. Let me know if you need help figuring out where anything goes since I have the full car.
Do you only have one esp sensor in the a4? Here are the two from the s4 in case you need part numbers. received_547436982773152.jpeg

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Thanks for that picture! I had the full car as well! Here's the thing, I'm not intimately aware of which cars got the ESP sensors. I figure it was any car with active steering or a sport diff. The S4 I've been tearing apart specifically, had the sport diff. My personal A4 has active steering and I am assuming it has both sensors.

this is amazing info thanks. i think soon we'll be able to decrypt exactly what needs swapped, so are there extra esp sensors related to the sport diff or are those in every s4 as part of the traction control system? i'm guessing can wiring is not resistance critical as it is just data connections and i wonder if they could be spliced into the canbus wiring anywhere, like in the trunk. not exactly sure how canbus works itself. is it just a data highway with free on/off access at any point?

I think that if the car has ESP sensors, it has 2 by default. Based on the self study's I've read, they both send out the same signal. One is for a main signal. The other is for redundancy and accuracy.

I'm not entirely sure how the CAN bus works either. I know that all parts in a specific part of the system are interconnected. I think that because they are individually powered, they communicate based on what kind of voltage/amperage they send out. Just what I think without having gone too deep into the theory of it.

You can splice into the CAN bus anywhere, location is not critical, as long as you find the correct CAN bus, there may be several separate CAN busses (Powertrain CAN, Infotainment CAN, Comfort Systems CAN...)....not sure about the S4.

While I don't doubt that the wires could be spliced in anywhere, I wonder why Audi engineers routed the wires all the way to the front in the drivers kick panel for it. Could it be that having the wires splice in close to where the active steering module would be allows for a faster response? Could it be so that all the data intersects in the same spot? Was it to save money because the sport diff is an option and not standard?

Here is a picture of the full sport diff harness that I pulled out from my donor. There isn't fabric tape on as much of the harness from the factory as can be seen in the pictures. I applied tape from the main body harness as I pulled it apart.

[avantagg]

Thank you guys for the detailed info! The is super helpful for anyone looking to do future swaps.

[zgastin]

Hey, anyone have an idea if you can drive on the sports diff while it is not connected?
My plan for the swap is to get the main mechanical stuff in first, and then add the accessories as I have time. Being able to test drive the car once the engine starts would be ideal.

Really interested to see what my a4 avant has in terms of esp.

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[Audi 4 Life]

No that is a bad idea. You need to do the wiring harness at the same time the only thing you can maybe delay is the coding which is pointless this isn't something to do in pieces. Do it right or do it twice (or more).

Thanks for all the info on the wiring i wish i had that when doing my manual swap i would of done this.... Oh well.
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[S4'ed]

I think it would be fine to drive it without the sport diff being wired/powered up. The rear diff just acts like a normal open mechanical diff, no harm. This is the factory "fail safe" mode if the fuse blows, or there is something wrong with the Sport Diff control electronics....the car can be driven forever like this, just fine.

From the Audi Self Study Guide on the Sport Diff: (Audi New Technology 2009 – 2010 Self-Study Program 990193)

"The sport differential functions as a normal open
differential when the multi-plate clutches of the speed
modulation boxes are not engaged."

[S4'ed]

The factory wire harness, for the CAN connection of the Sport Diff "All Wheel Drive Control Module" J492 goes to the front of the car to connect to the "Suspension Sensor CAN Bus", because that CAN bus is only present in the front of the chassis, where the following items are, that talk to each other on this CAN bus:
J104 ABS/ESP Control Module
G200 Transverse G sensor
G202 Rotational Rate G sensor
G251 Longitudinal G sensor
G419 ESP sensor #1
G536 ESP sensor #2
J792 Active Steering Control Module

You can see the whole sport diff wiring diagram at alldatadiy.com, for a B8 S4.

As a side note, as long as you maintain the wires as a twisted pair, and connect them in the right "polarity" (CAN H versus CAN L), the wire length (there is some practical limit) and resistance are not critical to the operation of the digital communication across the CAN bus.

[MagoAmado]

So after looking at the wiring diagram for the ABS unit I've come to find that sensor G419 is on all vehicles. Sensor G536 is saved for special equipment. This is good news in the sense of not needing to run a wire all the way to the ABS unit (J104). Sensor G536 splices into the CAN at the same spot as the sport diff and sensor G419, it goes to the same ground as sensor G419 and it splices into the ABS wire that feeds G419. This means that theres no need to swap out the full harness if all you're after is the sport diff!

[zgastin]

Thanks, great info!

I think it would be fine to drive it without the sport diff being wired/powered up. The rear diff just acts like a normal open mechanical diff, no harm. This is the factory "fail safe" mode if the fuse blows, or there is something wrong with the Sport Diff control electronics....the car can be driven forever like this, just fine.

From the Audi Self Study Guide on the Sport Diff: (Audi New Technology 2009 – 2010 Self-Study Program 990193)

"The sport differential functions as a normal open
differential when the multi-plate clutches of the speed
modulation boxes are not engaged."

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[avantagg]

Zach you should be fine. I spoke with Mike who did the first MT S4 avant swap. They put a sport diff in his but never actually wired it up. He told me it ran fine, just wasn’t able to activate the “fun” features. It will essentially operate as if always in non-dynamic mode.

[fastboatster]

So after looking at the wiring diagram for the ABS unit I've come to find that sensor G419 is on all vehicles. Sensor G536 is saved for special equipment. This is good news in the sense of not needing to run a wire all the way to the ABS unit (J104). Sensor G536 splices into the CAN at the same spot as the sport diff and sensor G419, it goes to the same ground as sensor G419 and it splices into the ABS wire that feeds G419. This means that theres no need to swap out the full harness if all you're after is the sport diff!

Well, does that mean that used sport diff eBay prices will skyrocket now?)

[sbw]

subbed for updates on this. I'd like to do a swap myself.

[hardfive]

Can confirm, thanks to work/research of Magoamado we swapped the s4 bits into my 2011 avant, including the sport differential, and it works BEAUTIFULLY.

[fastboatster]

So in short, did you have to do any wiring or you were able to purchase a wiring harness and plug it right in?

[hardfive]

So in short, did you have to do any wiring or you were able to purchase a wiring harness and plug it right in?

Mago amado stripped all the necessary wires out of the s4 harness and ran them I'm my avant body harness. We had to drill a hole in the body as avants dont have one. Not easy but you can, with patience, retrofit a sport diff into a car that didnt have it from.the factory.

20191220_195323.jpeg20191221_134302.jpeg20191221_135056.jpeg

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[hardfive]

Wiring went all the way up under the steering wheel. Kits has cut wires may or may not be an issue to extend but that first pic of the kit is cut.

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[fastboatster]

Hmm, if I have an S4 without a sport diff, would I need to mess with wiring harness? I probably don't need to drill any holes. But oh well, I'm most likely will never do this.

[S4'ed]

You would still need to add wires for retrofitting an S4.

[chrismadson]

Bumping an old thread…

Looking to do this swap in my 2013 S5 DSG and am wanting to confirm that as long as I get a sport diff from a DSG car, I won’t need a different driveshaft, just axles. When I do parts searches, I don’t see different drive shafts for sport vs non, just DSG vs Manual.

I may have more wiring questions once I know how much of the harness that I will be able to source.

Thanks!


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[wrxkyle]

Bumping an old thread…

Looking to do this swap in my 2013 S5 DSG and am wanting to confirm that as long as I get a sport diff from a DSG car, I won’t need a different driveshaft, just axles. When I do parts searches, I don’t see different drive shafts for sport vs non, just DSG vs Manual.

I may have more wiring questions once I know how much of the harness that I will be able to source.

Thanks!


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pretty sure the drive shafts are the same. you'll want to make sure you have the same final drive to match your center diff which varies by year and model sometimes. that will come up when choosing that actual diff to buy. there could be some same-year differences to be aware of like the v1/v1.5/v2 trans eg 2013 some had the v1.5 some had the v2 with the crown gear, not sure if it matters. i do beleive that the axles are different lengths and that the sport diff is notably wider. i think one axle may be the same and one side may be shorter. you'll have to double check that. but the actual driveshaft connection i believe to be the same length.

one thing from further up in the thread about adding their own wiring not working, i see that the wires in the post above's pics are twisted pair, it may be that the other ones were not twisted or were not twisted at the correct rate causing interference more than voltage sensitivity? i know in cat5 cable each conducter pair runs at a different twists-per-inch rate to reduce crosstalk which may be how the wire harnesses are done as well so you'd want to try and get the same gauge wire and maintain the same twists per inch (anchor one end of wire, chuck other in drill, spin while applying taught pulling pressure, stop and count twists per inch (count more than an inch lengths of twists and divide by inches, like how many twists in 10 inches etc, for accuracy, you can't really eyeball 1.2 vs 1.5 tpi looking at a wire without a heck of a lot of (niche) experience.

[chrismadson]

pretty sure the drive shafts are the same. you'll want to make sure you have the same final drive to match your center diff which varies by year and model sometimes. that will come up when choosing that actual diff to buy. there could be some same-year differences to be aware of like the v1/v1.5/v2 trans eg 2013 some had the v1.5 some had the v2 with the crown gear, not sure if it matters.

one thing from further up in the thread about adding their own wiring not working, i see that the wires in the post above's pics are twisted pair, it may be that the other ones were not twisted or were not twisted at the correct rate causing interference more than voltage sensitivity? i know in cat5 cable each conducter pair runs at a different twists-per-inch rate to reduce crosstalk which may be how the wire harnesses are done as well so you'd want to try and get the same gauge wire and maintain the same twists per inch (anchor one end of wire, chuck other in drill, spin while applying taught pulling pressure, stop and count twists per inch (count more than an inch lengths of twists and divide by inches, like how many twists in 10 inches etc, for accuracy, you can't really eyeball 1.2 vs 1.5 tpi looking at a wire without a heck of a lot of (niche) experience.

That’s an amazing information, thank you!

I think in 2013, Audi made the change to all b8.5’s having the crown. That being said, I wonder if there is a difference whether or not the diff came out of an S5 or an A/S6 or 7. Either way, I will definitely start researching!


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[chrismadson]

pretty sure the drive shafts are the same. you'll want to make sure you have the same final drive to match your center diff which varies by year and model sometimes. that will come up when choosing that actual diff to buy. there could be some same-year differences to be aware of like the v1/v1.5/v2 trans eg 2013 some had the v1.5 some had the v2 with the crown gear, not sure if it matters. i do beleive that the axles are different lengths and that the sport diff is notably wider. i think one axle may be the same and one side may be shorter. you'll have to double check that. but the actual driveshaft connection i believe to be the same length.

one thing from further up in the thread about adding their own wiring not working, i see that the wires in the post above's pics are twisted pair, it may be that the other ones were not twisted or were not twisted at the correct rate causing interference more than voltage sensitivity? i know in cat5 cable each conducter pair runs at a different twists-per-inch rate to reduce crosstalk which may be how the wire harnesses are done as well so you'd want to try and get the same gauge wire and maintain the same twists per inch (anchor one end of wire, chuck other in drill, spin while applying taught pulling pressure, stop and count twists per inch (count more than an inch lengths of twists and divide by inches, like how many twists in 10 inches etc, for accuracy, you can't really eyeball 1.2 vs 1.5 tpi looking at a wire without a heck of a lot of (niche) experience.

Just ordered the parts for the swap… we’ll see how it goes!


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[ak-s4]

None of the B8/B8.5 S4's came with the crown center differential.

https://www.audizine.com/forum/showt...1#post14423248

[wrxkyle]

None of the B8/B8.5 S4's came with the crown center differential.

https://www.audizine.com/forum/showt...1#post14423248

so in what ways then is the 2014 trans reinforced/better than the 2011 trans? no real differences?

[ak-s4]

so in what ways then is the 2014 trans reinforced/better than the 2011 trans? no real differences?

The DSG had a few updates over the years to improve reliability. Gen 1, Gen 1.5 and Gen 2. One major issue I know was fixed was that fluid would leak onto a PCB causing failures.

[chrismadson]

None of the B8/B8.5 S4's came with the crown center differential.

https://www.audizine.com/forum/showt...1#post14423248

My understanding was that the facelift cars (B8.5) had the crown gear as long as you had the DSG… at least for 2013.


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[ak-s4]

My understanding was that the facelift cars (B8.5) had the crown gear as long as you had the DSG… at least for 2013.


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Until someone posts some evidence of this, the answer is no.

[chrismadson]

Ok… so I have 2 swap sets and now I am thinking I may end up selling the car. Both sets have the diff, controller, yaw sensors, control unit, wiring harness… basically everything except for the CAN wires from the diff to the front. One set has axles and the other doesn’t. Is this something anyone would want?

Trying to decide if I will install or sell…


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[They'reBBBB8]

Hi, looks like this thread has been quiet for a while, but found this all really helpful. Just followed everything here trying to retrofit the sport diff during an S4 Avant swap. My donor S4 was hit in the rear quarter and the diff/shaft was in bad shape (open diff) so figured why not add this retrofit while I'm at it. From the other Avant swaps I've seen, the retrofit was more of moving the system from a donor that already had a sport diff. As of now everything is installed and wired up and of course it threw all errors, trying to calibrate the sensors but seems like a waterfall of errors/coding and confirming my modules will work. So figured I'd touch base here to see if anyone has experience activating/calibrating this in VCDS? Also going to start a Ross-Tech thread and hopefully pass on any info I can here.

[They'reBBBB8]

Ok, with troubleshooting help from Matt in the 3.0 Swap the world group on Facebook. I was able to narrow it down to the small black wire in the Diff Harness which is supposed to run to a constant fuse block, I added in a fuse next to the main power red/white wire. I had originally run it from a bundle of black wires in the main harness right behind the passenger (right) side wheel well. It wasn't getting any voltage when the car was ignition on. But now I'm finally getting a signal from the AWD module and a bunch of errors. Now to start coding and find someone to remove component protection...

The changes I've made so far are;
Can-Gateway - Install list - Checked the "AWD" box.
Instruments - Channel 4 - Bit 7 - Checked "Quattro Sport Rear Differential Installed"
Central Electronics - Channel 8 - Bit 5 - "Quattro Sport Differential Involvement with Drive Select/Charisma Active"

[Akis]

Did you manage to get the swap working 100% like factory? Also wondering if this is possible on a B9 S4...

[johnsonliu51]

Hi, looks like this thread has been quiet for a long time. I'm currently working on retrofitting the sport diff on my 2014 s5 and it has lot of problems. My car doesn't have active steering nor the sport diff. I wonder will sport diff work without active steering insatlled? Can they work seperately or are they just need to be both installed? The second problem is the abs module. The awd control unit cannot commute with the abs module. I double checked the wiring and there's nothing wrong with it, I think it needs some coding work on the abs module. Anyone knows the abs coding after retrofitting the sport diff?