Audi B8 S4/S5/TT Seats into MK6 GTI Installation Guide

Nov 05, 2021

My original GTI leather seats look good and hold me pretty well until I get close to 1 lateral G on the raceway or canyons!

They also have a mechanical lever for simultaneous adjustment of the seat height and angle. That means that you can't keep the seat at it's lowest position while tilting only the front edge of the cushion.

VW GTI seat controls

Audi B8/B9 Sport/SuperSport seats seemed like a decent upgrade. They look even better and have fully electric and independent seat adjustment controls. There is an Alcantara version with cloth centers and leather bolstering. Alcantara (aka velvet) keeps your body in place noticeably better and won't get you sweaty pants and shirt in summer as easily as non-ventilated leather does.

Audi seat controls

In fact Alcantara seat center makes getting in and out of the seat a little more cumbersome since you can't just drop you butt at any angle and simply slide on the seat afterwards.

Audi SportSeat has an extendable knee pad (support) which I thought was nice but in reality doesn't work for me.

SuperSport seats come in a long list of Audi models: S4, S5, TTS, some TTs and probably RS models too. Even recent RS3 generation seats look very similar, hence (in theory) could be installed into MK5/MK6/MK7 GTI and R. You can find them on your local european pull-a-part salvage yard, craigslist, ebay and alike.

I bought mine on ebay. Both seats came out of Audi S4 but were taken out of different cars - driver's seat had 2013 production date while passenger's was labeled as 2009. They look absolutely the same though, and down the line it didn't cause any difficulties.

Audi SportSeat in MK6 VW GTI

Before we jump into the installation, let's talk about electric modules of the seat. Surprisingly (at least for me) there is enough to talk about!

Electric Modules of the VW seat

Seat modules:

  • seat adjustment motors (including lumbar support) and buttons
  • seat position memory module (some Audi cars only, as fas as I know not applicable to US GTIs)
  • heating module, heating elements and temp sensors
  • occupancy sensor (passenger seat only)
  • seat belt switch (including belt tension sensor on GTI on the passenger side)
  • seat position sensor (driver seat only on GTI, both sides on Audi)
  • Audi seat also utilizes the rear passenger footwell light (not applicable to GTI)

Each seat is made of two separate steel frames: seat bottom and backrest. They can be separated by unscrewing two triple square bolts on each side and freeing electric cables to backrest motors.

Audi seat service position

Seat Adjustment Modules

GTI seat adjustment buttons and motors work together as independent unit, meaning that there is no CAN bus connecting them with a comfort control module of the car.

From Audi seat installation perspective it means that supplying power and ground wires (protected with an appropriate fuse) is sufficient to get all the adjustment motors and buttons work.

We will be reusing the "internal" Audi seat wiring between seat buttons and motors.

You can also check your seat adjustment motors while seats are out of the car using an external 12V power supply (i.e. car or motorcycle battery).

Seat Heating Module

Each seat has two heating elements - one in the seat bottom and another one in the backrest. Temperature sensor is located in the seat bottom only.

There is a dedicated heating control module (marked as J774 on VW electric schemes) under the driver's seat responsible for heating up both seats. That's right - power for passenger seat heating elements is supplied by this module.

Heating control module is connected with climatronic and AC control modules which are located somewhere in the dash.

PODS System

Passenger occupant detection system (PODS) responsibility is to figure out if the front passenger airbags should deploy (and, probably, to which extent) when car gets into an accident. It's control module is located under the passenger seat and uses two sensors to make the call - pressure sensor mat in the seat bottom and seatbelt tension sensor in the passenger seatbelt buckle.

PODS control unit is connected to the airbag control module with two CAN wires.

VW GTI seat PODS system scheme

Seat Belt Buckle Switch

Driver's seat belt buckle in 2013 VW GTI operates as an inverted switch. Fastening the belt brakes the circuit.

It's passenger seatbelt switch provides 400 Ohm resistance when unbuckled and goes down to 100 Ohm once buckled. Passenger seatbelt also has the belt tension sensor built into it which operates as a potentiometer.

Seat Position Sensor

Installed on the driver's seat rail seat position sensor communicates seat position to the airbag control module under the dash to modulate driver's airbag deployment in case of an accident.

Seats Installation

Disclaimer: Use at your own risk! Don't consider this information a guidance. Interfering with original car electronics and mechanics is risky, not recommended and can cause a serious injury or death. Author doesn't assume any responsibility or risk caused by your actions based on this post.

There are two main steps: physically bolting seats down and connecting them to the electronic system of the car. You might also need to disassemble the Audi seat bottom to retrofit PODS sensor into it.

Mechanically Audi B8/B9 seat is almost a direct fit for the VW Golf platform. All you need is to cut one of the seat positioning pins from the outer seat rail. Both Audi and VW use two positioning pins sticking out of the seat rails. However, VW places both positioning pins on the inner seat rail while Audi places one positioning pin at the end of both rails.

Once the redundant pin is removed (no big deals since it's made of aluminium), Audi seat can be bolted right into the Golf body using original fasteners.

Audi seat backrest is a little wider, taller and thicker than GTI seat. Seat bottom will be almost at the same height, may be half of an inch higher in its lowest position. Which kinda sucks cause GTI's own seat is sitting quite high.

I've experienced some rubbing of an Audi seat against the armrest cover and rear central console. Not much to worry about since you can hear it only moving the seat forward and aft. Also folding of the rear seat becomes more of an issue - you might want to remove those headrests.

VW GTI folded rear seats wo the headrest

Audi seat is also noticeably heavier than GTI one: 28.5kg vs 24.5kg. Extra four kilos (nine pounds) doesn't sound like much, but they do make seats installation (and removal) significantly more physical.

On the electric side of things we will be reusing VW's heating and PODS control modules while leaving all Audi seat motors, buttons and sensors in place. Generally speaking - all we have to do is to replace seat-to-vehicle connectors. Most of the "internal" Audi seat wire harness remains in place.

I didn't want to cut my VW seats wire harness and bought two used ones on ebay. For best match check labels under your seats but for 2013 GTI with heated leather seats and electrical backrest adjustment codes are 5K0 971 391 R for driver's seat and 5K0 971 392 BC for the passenger's.

Theoretically you can get away with buying just seat connectors and using Audi wires only. Undoubtedly such approach would require more work on the wiring, pins, etc.

Some Audi seats have seat adjustment memory control modules, and we won't use it (I doubt that is possible/feasible to use Audi control modules on Golf platform anyway).

Passenger Audi seat I bought didn't have the occupancy sensor (PODS seat bladder) hence I had to buy it (more on that below). If your seat comes with it, you should be able to reuse it.

Driver's Seat Installation

Seat Adjustment Motors and Buttons

This is probably the easiest part of the installation.

We need to connect red/black and brown wires removed from the red Audi connector with matching color wires going into the black T10a VW connector (pins 9 and 5 respectively).

And that is it! To make all the adjustments work all we need is to supply power and ground. All the internal seat wiring between motors and buttons remains as is.

This step might differ if your Audi (or VW) seat came with the seat position memory module.

Heating

Internal VW driver's seat wire harness comes with three connectors related to heating:

  • T8z - heating module connector
  • T2d - backrest heating element
  • T4l - seat heating element and temp sensor

Audi seats heating wires however can be connected with the main seat harness via single connection point and backrest will be getting it's power supply from there.

So, we can cut off the T2d connector as well as wires coming into it. Then cut T4l connector and connect four wires going into it with the Audi seat heating wires (green connector).

VW color listed first:

VW ColorAudi Color (green plug)Description
green (1mm)red/white (1mm)heater power
brown (1mm)grown (1mm)heater ground
black/blue (0.5mm)black/white (0.5mm)temp sensor power
brown (0.5mm)green/brown (0.5mm)temp sensor power

internal heating wiring

Now we can connect and install VW heating module under the seat frame. Front right section has plenty of space and two zip ties will keep it in place.

VW GTI Seat Heating Scheme

Driver's Seat Buckle Switch

Unfortunately we can't just plug the Audi seat belt buckle wires into the matching VW connector because Audi uses completely different switch schematics.

Audi buckle switch reads 400 Ohm resistance when unplugged which drops to 100 Ohm once the belt is buckled.

GTI driver's belt switch operates as an inverted switch - it works as a closed circuit when unlocked and opens up when locked (seat belt fastened).

You might think it should be the other way around: open when unlocked and closed once locked, but it is, in fact, inverted.

We can't bolt VW buckle switch onto the Audi seat either because their seat rail mounts are very different.

VW and Audi seat belt buckle switches

I decided to leave driver's seat buckle switch connector T2q open (not plugging anything into it). Basically it means that GTI considers driver's belt buckled in at all times. I never drive without the belt and don't need a reminder to put it on.

Side effect of this approach is that the red unfastened driver's seatbelt icon won't appear on the dash when the car ignition is turned on and belt is not yet fastened. Savvy used car buyer might notice that.

Theoretically we can open up both buckle cases and swap the internals.

Yet another option is to find an old Audi seat belt buckle switch which is using the same schematics as VW's one. Please let me know if you manage to find it!

Seat Position Sensor

We need to replace seat position sensor black connector with the black VW T3k connector. There are only two wires to connect: red from the sensor with blue coming into the connector and both ground wires colored brown.

seat position wires

I tried to validate correctness of Audi sensor with VCDS Adv. Measuring Values but was constantly getting position: rear reading no matter what.

VCDS Measured Values for the seat position sensor

Which means one of the two things - either Audi sensor is not working properly (i.e. has to be calibrated) or original reading is in fact (almost) always the same.

Passenger seat wire mapping

Wrapping Up

Now we can cut off all unused wires and plugs left in the VW harness (meant for VW seat adjustment motors and buttons) and bolt the seat into the car.

Driver's seat wire mapping

We can have Audi driver's seat installed into the car and VW passenger seat fully operational without any errors on the dash. I think the opposite is also true but personally didn't try it.

Passenger Seat Installation

Passenger sear installation is very similar to the driver's seat installation except for PODS module and related sensors.

VW GTI passenger seat wire harness

Seat Adjustment Motors and Buttons

Similar to driver's seat we have to connect just two wires to get seat adjustment buttons and motors work:

  • brown wire coming to T10b connector with brown wire cut out of the red Audi connector
  • red&black wire coming to T10b connector with red&black wire cut out of the red Audi connector

Last two thin black/green and brown wires coming out of the same red connector are responsible for rear passenger foot-well light and won't be used in GTI since we don't have anything to connect them too (unless you want them to work all the time when ignition is on).

Since we are using Audi's internal wiring between motors and buttons we need to cut and isolate all VW seat motor power wires from the "internal" VW seat harness.

Heating

Wires mapping:

VW Color (T10b connector)Audi Color (green plug)Description
violet/blue (1mm)red/whitepower for heaters
brown (1mm)brownground for heaters
violet/blue (0.5mm)black/whitepower for temp. sensor
brown (0.5mm)green/brownground for temp. sensor

PODS System

Audi passenger seat came without PODS sensor hence basically I had three options:

  • mock PODS sensor with the static voltage divider (similar to the one described below for seat belt potentiometer)
  • buy Audi sensor along with PODS controller (which look exactly like VW's one) and connect those to the VW seat harness
  • buy VW sensor and try to fit it into the seat between the cushion and steel frame

I didn't like first option cause the only safe way to go that route is to make the car "think" that front passenger is always present. Which is far from ideal because it would require passenger seat belt to be buckled all the time (unless coded out) and in case of an accident passenger airbags will come off even when, in fact, there is no passenger in the front seat.

Instead, I went with option two and bought Audi PODS sensor with the controller. I was able to install sensor into the seat without any problems. Audi controller didn't work however even though all the related connectors are exactly the same as VW ones.

Audi PODS sensor being installed into Audi seat

I had to swap PODS controller from my origin VW seat and even then I had an issue when calibrating sensor through VCDS. I guess it is caused by Audi sensor having different shape and subsequently different resistance (voltage) curve based on the pressure applied to it.

If I remember correctly VCDS Advanced Measurements was showing 50 as a base (no load) value for VW seat sensor while in Audi seat that value is around 110.

VCDS PODS System Measured Values

I assume calibration was failing because of the base value being out of the range. And without proper calibration I was getting calibration required error and orange warning light for the passenger airbag on the dash.

I ended up connecting my VW PODS sensor just to have calibration done, switching the car off and reconnecting the plug to the Audi PODS sensor. It did work but not without caveats.

First thing I noticed is that even though orange light on the dash would be showing that passenger airbag is off (since passenger was not detected by PODS sensor) my dash would still be showing a warning that front passenger is not buckled and play that annoying chime.

I had to code the Unbuckled warning out with the help of VCDS (Instruments module). Again, not ideal but I couldn't figure another way. My assumption is that the dash has certain expectations regarding PODS sensor base (no load) value.

Now I can drive around without any warnings and "airbag disabled" light shows up when there is absolutely no additional weight on the passenger seat. But once I put my backpack on the seat the light turns off. Which means that in case of an accident most probably passenger airbag will fire up! So, in a sense we are back to the cons of option one.

That's why I've added option three to the list - using VW PODS sensor on the Audi seat. However, since shape of the bottom frame is quite different between the two it might be a challenge to get it installed properly.

Seat Buckle Switch

There are five wires coming out of GTI passenger's seatbelt buckle switch: two to figure out if the belt is fastened and three more to measure tension on the fastened belt.

Generally seatbelt tension is very low (can be checked with VCDS) when passenger is present (or not) and very high when child seat is installed.

Seat buckle switch coming with Audi seat has only two bright-green wires used to determine the locked/unlocked status of the belt.

Since we can't bolt VW seatbelt buckle switch onto the Audi seat we have two options:

  • mock the seat tensioner in some predefined position with a voltage divider. So that the car "assumes" that there is always a "real" passenger on the seat rather than a child seat.
  • buy another Audi seat buckle for the passenger seat which comes with the potentiometer similar to the one used in VW

First I came up with the voltage divider to drop voltage from 5V to 1V using 2 KOhm and 500 Ohm resistors. That worked pretty well.

Then I found that there is an Audi A8 seat belt buckle switch which is using five wires. It's connector to the seat rail a little shorter than the original Audi one but works just fine. Part number is 4H0 857 756 A.

Audi seat belt buckle switches

Wire mapping for the seat belt buckle switch position (VW color goes first):

  • brown color with one of the green colored wires of Audi buckle switch
  • purple color with another green colored wire

GTI has a yellow plug T2y to connect this pair of wires to the car.

Wire mapping for the seat belt tension potentiometer (VW color of wire from the PODS module goes first):

  • brown to black (ground)
  • yellow to blue (reduced voltage)
  • black to red (constant 5V)

Passenger Seat Buckle Switch connectors

A8 belt buckle potentiometer uses exact same color scheme as VW one. You can either cut the VW female plug and connect wires directly or buy male plug on aliexpress and connect them with proper plug. (I tried the latter but failed to find the right one).

We don't need Audi seat "internal" wiring for position sensor and seatbelt and can remove it completely along with the corresponding connector and seat position sensor.

No calibration is needed for the newly installed Audi seat buckle switch.

Closing notes

Have to admit that installation was more involved than I originally thought it would be. Hardest part was to figure out how to fake (or retrofit) PODS sensors.

Regarding seats themselves and whether the retrofit is worth or not it's hard to for me to say. I wish they provided even more lateral support. They are totally adequate for the street and canyon driving but not for the track I'd be looking into "real" bucket seats instead. Probably not even Recaro Speedster GT/CS.

I also want to seat closer to the floor and Audi seats don't help me with that at all.

They do feel and look better than original GTI seats and electrical adjustments are hard to beat. Hence, choice is yours and either way - good luck!

Various Codes and References

VW Seats to Car Body Connector Codes

Driver side connectors

CodeDescription
T10aseat adjustment and heating (master)
T2qseat buckle switch connector
T3kairbag connector
T3brseat position sensor

driver VW seat connectors

Passenger side connectors

CodeDescription
T10bseat adjustment and heating (slave)
T10ePODS connector
T2yseat buckle switch connector
T3lairbag connector

passenger VW seat connectors

Internal VW GTI Seat Connector Codes

CodeLocationDescription
T8zdriver seat8-pin heating module connector
N/Apass seat3-pin potentiometer connector
T4mpass seat4-pin heater and sensors connector
T2epass seat2-pin backrest heater connector
T18fpass seat18-pin PODS module connector

Electric Scheme Component Codes (VW GTI)

CodeComponent Name
J706PODS control module (passenger seat)
J774heating control module (driver seat)
G452passenger occupant detector sensor
G453PODS seat belt force sensor
E24driver seat belt switch
E25passenger seat belt switch
G553driver seat position sensor
E470driver seat recline button (?)
E471passenger seat recline button (?)
J234airbag control unit (central dash)
J255climatronic control module (central dash)
J301A/C control module
Z6driver seat heating element
Z7driver backrest heating element
Z8passenger seat heating element
Z9passenger backrest heating element
G59driver seat temperature sensor
G60passenger seat temperature sensor

Audi Seat to Car Body Connectors

Generally speaking:

  • red plug has power supply and ground wires for seat adjustment motors and buttons
  • black plug has wires for Audi seat buckle switch and seat position sensor
  • green plug has heating and temp sensor wires

Driver Seat Connectors

Audi drivers seat to body connectors

Passenger Seat Connectors

Audi passenger seat to body connectors

Related Part Numbers

  • driver VW seat wire harness: 5K0 971 391 R
  • passenger VW seat wire harness: 5K0 971 392 BC
  • VW seats heating control module: 5K0 959 772
  • VW seat occupancy (PODS) sensor: 1K0 959 337 D
  • Audi Sport seat occupancy sensor: 8T0 963 553 E
  • driver audi sport seat airbag: 8K0 880 241E
  • passenger Audi sport seat airbag: 8K0 880 242E
  • passenger Audi seat adjustment button unit: 8K0 959 748 C
  • passenger Audi S8 seat buckle switch: 4H0 857 756 A

References:

  • VWVortex topic which helped me quite a bit and motivated me to post this guide here. Has very useful scheme of wire colors used by VW and Audi seat connectors.

  • Golf MK6 Wiring Diagrams. Don't worry about russian language, just wait for a couple of seconds and click the filename vw-golf-6-wiring-diagrams-eng.pdf to download the pdf. File itself is in english.

  • Golf MK6 Component Locations. Same as above - wait for a few seconds, then click the file name to download it.

If any of the resources above go down please ping me to have them updated. Good luck!