# How to: Audi TT Mk2 (8J) Convertible Roof Flap Servo R&R



## SwissJetPilot (Apr 27, 2014)

*Scope - *

One of the most common problems with the roof not working is due to a fault code from the convertible top *R*oof *F*lap *S*ervos (*RFS*). If your top suddenly stops working, or doesn't open or close all the way, or if the windows stop working correctly odds are good one or both of the RFS is to blame.

Fortunately it's a simple DIY to sort it. However, it may require a VCDS to run the Adaptation* if a fault code has been registered. Simply clearing the fault will not make the problem go away.

* *UPDATE* - I have tested the OBDeleven and while it can be used to find and display a roof-related fault codes, it does not have the ability to run the Adaptation or clear the faults for this problem. You can read more about OBDII diagnostic devices *here*.

If you are experiencing problems with the roof operation and there are no fault codes reported, then you can still go ahead and perform the servo cleaning as described below and a VCDS may not be needed.

*NOTE - Downloadable PDF file for these instructions with more detail are available at the bottom of this page.*


















*Overview -*

The RFS has two primary components; the Motors (V381 & V383) and the Potentiometers (G596 & G597). When energized, the motor drives the potentiometer gears which move the servo arm and ball link to raise and lower the flaps. At the same time, the potentiometer sends a real-time position signal to the J256 Convertible Top Operational Control Unit (CTOCU) so it knows if the flap is open or closed. In the event the servo gives a false or out-of-tolerance reading (implausible signal), the CTOCU will lock out the E137 switch (center console roof switch) which will prevent the top from moving to avoid a collision between the top mechanism and the flaps.

Think of the potentiometer like a dimmer switch; turn it one way the light gets brighter, the other way, the light gets dimmer. This is because the voltage changes as the dial is rotated. In the same way, the roof flap potentiometer provides the CTOCU with a high or low value so it "knows" if the flap is up or down.

For a more detailed explanation on how the convertible top works including Measurement Blocks, Fault Codes and Adaptaion, click *here*. Also it's worth reading through *Self Study Program 391* linked *here*.

*The Cause of the Fault -*

Over time, the grease inside the servo housing can migrate from the gears onto the potentiometer and gunk-up the electrical contact between the circuit board the little copper "fingers" on the contact gear. When this happens, a false signal or "implausible signal" can be generated which will result in intermittent operation of the top or no operation at all. While some service centers recommend replacing the flap servo, this doesn't always solve the problem since even new servos can eventually end up with grease in the potentiometer too.



























*Purpose of the Adaptation -*

When a fault has been registered, the Adaptation has to be performed to allow the CANBUS to establish the new max and min values of the potentiometer. Unlike a normal on-off switch which only has two positions, the potentiometer has a range of positions. The Adaptation allows the CANBUS to "learn" the new expected values for Group 001, Blocks 3 and 4 which should be between ~42 and ~184 as it moves the RFS potentiometer. This is why simply clearing the fault won't make the problem go away even if you've clean up the servos since the out of range values are stored until the Adaptation has been performed.

*Fault Scan for Soft Top Diagnosis -*

After running an Auto Scan, look under Address 26 Auto Roof. Reported roof flap faults might look something like this:

Address 26: Auto Roof Labels: 8J7-959-255.lbl
Control Module Part Number: 8J7 959 255 B
Component and/or Version: 256 VSG TT H14 0110
Software Coding:
Work Shop Code: WSC 00000 000 00000
VCID: 3E73D87369826EEEA6F-806B
4 Faults Found

-* 02000* Switch Position*
008 - Implausible Signal

- *00830* Convertible Top Control Module (J256)
004 - No Signal/Communication - Intermittent

- *03246* - Sensor for Canopy Flap; Left (G596)
008 - Implausible Signal

- *03247* Sensor for Canopy Flap; Right (G597)
008 - Implausible Signal

*This refers to E137 Convertible Top Operating Switch located in the center console.

In this case, the J256 Controller (P/N 8J7-959-255, located in the trunk) received an unexpected signal from the flap servos G596 and G597 and doesn't know if the flaps are up or down or somewhere in between. To avoid a possible collision between the top mechanism and the flap, it deactivates the E137 switch in the center console. When this happens, you can expect to see "*Soft top cannot be used*" displayed in the DIS.

*Getting Started on Repairing the Servos -*

*CAUTION* - Before removing the RFS from the vehicle, It's a good idea to place a towel down inside and around the area under the RFS. This will help prevent anything from falling into the "abyss" as recovering a dropped screw or bolt will be not be fun!

*NOTE* - These instructions are for both the left and right RFS. However it's recommended you only remove and repair *one at a time* to avoid mixing up the left one with the right one. _If you remove both RFS at the same time, it's a good idea to mark them "L" and "R" so you know which goes where. The left and right servos are exactly the same part, it's just flipped for left or right operation._

*GETTING HELP* - Since this topic has been coming up more frequently as the Mk2s continue to age, rather than addressing each and every Forum members post, I have created a Q&A post just for this topic. If you have any problems or questions about how to do the RFS R&R, please post them in the link below - 
*








Roadster Roof Flap Servo (RFS) Repair Questions and Answers


This post is provided as a Q&A post for anyone following the post How to: Audi TT Mk2 (8J) Convertible Roof Flap Servo R&R linked below. https://www.ttforum.co.uk/threads/how-to-audi-tt-mk2-8j-convertible-roof-flap-servo-r-r.1786641/#post-8851001 I have collected a number of posts and threads...




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*
*Tools You Will Need - *

• 10-mm socket
• T-20 Torx driver
• Business card, old credit card, stiff paper stock or an old aluminum soda can
• Isopropyl alcohol and/or electrical contact cleaner
• Paper towel, cotton swabs and/or soft brush
• *Ross Tech VCDS* for clearing error codes and performing the adaption of the flap motors. _As noted, no other OBDII device, including OBDeleven, has the capability to perform the necessary Adaptation and fault clearing._

*1 - Accessing the Roof Flap Servo* 

1.1 - Open the convertible top so it's in the stowed position. The procedure for manually opening or closing the top can be found *here*.
1.2 - Disconnect the ball-link from the flap and secure it to the clip on the underside of the flap so prevent it from getting damaged.
1.3 - Use a pencil or marker and draw a circle around of each of the four bolts. This will help you realign the bracket when you reinstall it later.
1.4 - Unscrew and remove the four 10-mm bolts holding the Flap Assembly.










*2 - Removing the Roof Flap Servos -*

2.1 - Unscrew and remove the three T-20 Torx screws and remove the RFS.
2.2 - Disconnect the RFS plug.
2.3 - Remove the RFS from the vehicle.








*3 - Opening the Roof Flap Servo Case -*

*NOTE* - Before opening the RFS case, use a white hobby marker and make a line on the arm and case so you can be sure the arm is re-installed in the correct orientation when you put them back together. See the photo in the *Trouble Shooting* section below for reference.

3.1 - If present, remove the Audi product sticker.
3.2 - Making shims: Shims will be used to keep each of the clips released during this step. You can use a business card, an old plastic hotel key or even strips from an aluminum can. Cut seven strips 1/4" wide x 1/2" long
3.3 - Wedge the shims into each of the seven clips to disengage them. Use care as you don't want to break them!
3.4 - Once all the clips have been shimmed, use a small flat screwdriver and starting at the plug socket gently pry the two halves apart. Then work around the two halves to separate them.









*4 - Remove Servo Arm and Disassemble Potentiometer*

4.1 - Once the RFS is open, you will see the three major components; the Motor, the Contact Gear and the Circuit Board. The Contact Gear and Circuit board are the two halves of the potentiometer. There are two traces on the circuit board and three copper "fingers" on the Contact Gear.
4.2 - To remove the Contact Gear, press the corner of the Servo Arm Axle inwards (arrow) and push the entire axle down and out of the Contact Gear. NOTE - Use caution not to put pressure on the Contact Gear as there are three very small contacts on the other side of the Contact Gear.
4.3 - Once the Servo Arm has been removed, remove the Contact Gear.
4.4 - Turn the Contact Gear over to reveal the contact "fingers. The circuit board and fingers are now ready for cleaning.









*5 - Cleaning -*

5.1 - After removing the Contact Gear, carefully remove excess grease from the three Contact Fingers. Be very careful not to bend or damage the fingers!
5.2 - Remove all excess grease and clean the circuit board traces (black concentric circles).
5.3 - Remove any excess grease from the back-half of the Servo Case.

*6 - Reassembly -* 

6.1 - Verify the Servo Arm orientation to the RFS case using the white lines you marked previously, and ensure the position of the arm is aligned correctly.
6.2 - With the Servo Arm in the correct position the Contact Gear is ready to be installed with "fingers" down against the circuit board.
6.3 - Press the Contact Gear fully onto the Servo Arm Axle. You should hear a "click".
6.4 - Align the front and rear cases and press them together. Ensure all clips are fully engaged.
6.5 - The RFS is now ready to be reinstalled in the vehicle.

*7 - Installation of the Servo to the Flap Assembly - *

7.1 - Connect the Servo Motor plug.
7.2 - Align the Servo Motor with the three screw holes. NOTE - Be sure to align the Servo Arm External Axle with the hole in the frame.
7.3 - Insert and tighten the three T20 Torx screws.
7.4 - Re-install the Flap Assembly with the four 10-mm bolts. (Tighten to 5-Nm).
7.5 - Connect the ball-link to the flap.

*VCDS Adaption of the Flap Motors -*

If there was a fault registered, an Adaptation must be performed or to the roof will not function. When performing repairs/replacement of the Flap Servos, it's necessary to use a VCDS to run an Adaption. If you just clear the faults and you don't run the Adaptation, the roof won't work.

For more information on the Adaptation and VCDS Measurement Blocks, take a look at the link below -








FAQ - Mk2 Roadster Convertible Measurement Blocks, Fault...


Section 1 - Convertible Top Fault Codes - When the roof fails to operate properly, it will require an OBDII scan device such as a Ross-Tech VCDS or OBD-dongle device; (e.g. OBDeleven, Carista, etc.) in order to identify the DTC (Diagnostic Trouble Code) and affected components. Since fault...




www.ttforum.co.uk





*[Select]
[26 - Auto Roof]
[Output Tests - 03]
[Select] Selective Output Tests
[Choose]Convertible Top Flap Initialization 
[Start]

Note* - At this point, the top is fully open and in the stowed position. When you hold the convertible top switch, the top will NOT fully cycle as you might expect. Instead, it will start to move the flaps, and then stop. At which point you release the switch and then hold it on again. The flaps will move again and stop. This will have to be repeated anywhere from 20-40 times until the flaps are all the way down so the top is in the fully closed position.

Now you can run through the full close cycle. As you did to lower the flaps, you will have to do this over and over (on-release-on-release) for the entire cycle to close and then open the top. This will take about 5-7 minutes. It's a good idea to have the engine running to keep the voltage up during this process.

*Be sure to operate the Convertible Top throughout a complete Close/Open sequence BEFORE exiting the Output Test function.

[Done, Go Back]
[Close Controller, Go Back - 06]*

*Expected Fault Codes -*

After completing the adaption, run an Auto-Scan to verify if any errors still remain.You may have some errors listed in the VCDS scan, for example:

Address 26: Auto Roof
3 Faults Found:
- 02000 Switch Position
008 - Implausible Signal
- 00830 Convertible Top Control Module (J256)
004 - No Signal/Communication - Intermittent
- 03246 - Sensor for Canopy Flap; Left (G596)
008 - Implausible Signal
- 03247 Sensor for Canopy Flap; Right (G597)
008 - Implausible Signal

Clear the errors and cycle the roof normally. Run a final Auto Scan to verify that the faults have been cleared and everything is okay.

*Trouble Shooting - *

After you have everything back together and the top still doesn't function properly, check the next thread for additional help -


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## SwissJetPilot (Apr 27, 2014)

*Trouble Shooting *

After you have everything back together and run the Adaptation the roof should function normally. However if you find the roof still doesn't operate correctly and there are no fault codes, there's a good chance you missed something when putting the RFS back together.

*1.) Wrong Servo Arm Position* - 

Verify that the servo arm is in the correct location. Double check the white marks you made on the arm and case are lined up as shown below. If you removed both the left and right RFS, be sure you didn't mix up the parts.









*2.)* *Bent Fingers* - 

Pay special attention to the little fingers on the gear as noted below. It's also possible that you may have installed the arm in the wrong orientation. Once installed, there should be no crunching or grinding noises coming from the servos during operation. If anything sounds wrong, STOP! Do not attempt to force the flap, link arm or the servo or you may break it. Remove the servo, check that everything is put back together correctly and try again.









_Turns out we had accidentally damaged one of the servos when reassembling._

_Using the VCDS application, we measured the values for each of the servos and the left one was always reporting 255 no matter what position it was in. Took it apart again, spotted the slightly twisted 'prong'. Re-aligned with a set of tweezers. Reassembled, adaptation done...everything working perfectly._

_Looking at what had happened, when we reassembled the servo, we put it in place, without fully closing the unit, made sure the servo arm was in the right place by rotating it without engaging the cogs, and then fully closing the unit. In doing so, the inner of the 3 prongs seems have been snagged on the rough edge of the servo arm spigot causing it to twist and lift away from the PCB tracks._

*3.* *Flap Over Extension Issue* - 

Adjustment of the flap opening angle is critical, particularly after replacement of the flap motors. This adjustment is checked by establishing a gap of 9.6 mm between the flap and the wind deflector. If a fully-open flap is in contact with a raised wind deflector (0 mm) or less than 9.6 mm, the flap has opened over-center. Please refer to this *TSB* for more information on this issue and how to correct it.









*4. Damaged Spur Gear - *

As shown below, this can happen for a couple of reasons -

• Someone forced the flap down resulting in the lever arm forcing the spur gear to turn against the worm gear.
• The motor was engaged while the roof flap was jammed or held in place, resulting in the worm gear cutting into the spur gear.

In either case, if this damage is present, it may be necessary to replace the entire servo.










*Additional Information -*

For additional information on VCDS codes, please refer to the Ross-Tech website -
Ross-Tech Wiki

For additional information on Convertible Top issues, please refer to this post -

*FAQ - The Ultimate Audi TT Mk2 (8J) Roadster Compendium *
https://www.ttforum.co.uk/forum/viewtop ... &t=1813290

For more information on the operation of the convertible top and all the system components, refer to Audi TT Roadster, Self Study Program 391 -

*FAQ - Audi TT (8J) Workshop Manuals & Self Study Programs*
https://www.ttforum.co.uk/forum/viewtop ... &t=1833829


*Replacement Parts and Repair Kit*

If the flap servo motor is damaged beyond repair, you can pick up a new one from Audi or a reseller; part number: *8J0 959 311 A*.

In the event the actuator arm or ball links are missing, damaged or broken, there is a repair kit available; part number: *8J7 898 943*.










You may find the replacement part number for the servo motor has a "A" suffix, while the one that came with the car does not. This may be due to how VAG deals with factory installed part numbers vs. replacement part numbers. There is only one part number for the servo motor, so there's no left or right as they are interchangeable. For more information on replacing a servo motor and installing the arms correctly click *here*.

*About the Ross Tech VCDS -*

Not everyone wants to drop $200 on a new HEX-V2, but for the price a service shop will charge you to do this service, it may be worth the investment especially if you like working on your own vehicle. But if you don't want to buy one, you still have a couple of options; check the Forum Sticky section for VCDS users and contact someone in your area and see if they're willing to do it for you. Or just take it into the shop and have them to it.
VCDS with HEX-V2 Enthusiast | Ross-Tech

*Audi TSBs for the Convertible Top - *

Audi is well aware of this problem, but hey simply advise that the servos be replaced. Unfortunately, you could just as easily end up right back where you started if that servo has too much grease inside too. You can read the applicable TSB *here* and *here*


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## SwissJetPilot (Apr 27, 2014)

This post is closed for comments. However, if you need any advice or assistance, please follow this post and use one of the links best suits your particular issue and post your comments or questions there.









FAQ - Mk2 Roadster Compendium of Convertible Soft Top...


This first link will take you to a comprehensive post on all things associated with the Roadster. For anyone new to the Forum, this is probably the best place to start. FAQ - The Ultimate Audi TT Mk2 (8J) Roadster Compendium https://www.ttforum.co.uk/forum/viewtop ... &t=1813258 1.)...




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