Audi S6 fuel filler cap error

Hey everyone,
"For some time now, I've been having a strange issue with an Audi S6 Avant 5.2 FSI in the workshop: the message "Tankdeckel Verschliessen" (which translates to "Fuel Tank Lid Closed") is appearing on the instrument cluster display. I've connected VCDS to read the error codes, but I haven't found any. I've also tested the individual control units separately, but still no errors. Does anyone have any ideas, or is something that needs to be programmed?" The fuel tank cap was also replaced, but without success.
Thank you in advance.

Hi,

How does the fuel door work? Does it have a button inside the car that opens it? Is everything working as it should?
Possibly, the sensor, whether it's open or closed, isn't integrated into the engine's mechanics, but is instead a separate component.

Best regards, Rainer.

Hi Rainer,
Thank you for the quick response. No, the fuel tank lid only has a servo motor with two wires (green/violet and green/gray). I completely disassembled the lid and there are no sensors installed. The central locking system works perfectly; it opens and closes without any problems. There is no button installed inside the car, but the instrument panel displays this message as shown in the photo. I have also checked the "Comfort" settings (code 46) bit by bit, and I haven't found any errors. I also tried using the coding assistant to enable and disable the "fuel tank lid open" function (even though, as I said, there is no button inside), but without success. I'm almost certain that there's a coding error, but I have no idea which module it's in. "The customer says he installed the LED daytime running lights himself two months ago and programmed them with VCDS, but this message has appeared for about two weeks."

Oh dear, that really sounds like it's misconfigured.

Are you absolutely sure that the fuel cap doesn't have another sensor? I mean, besides the one connected to the servo motor. Theoretically, one could analyze the current consumption of the servo motor to determine its open/closed state.

Quote:

"Fuel cap lock"

It means that, according to him, the corresponding control unit is still accessible or hasn't been locked. It's possible that the opening/closing mechanism isn't moving far enough due to a mechanical issue, such as a foreign object, wear and tear, or something else.

Do you have a car scanner?

Perhaps you'll get lucky and the fuel cap is a "S6 specialty," and you can find a similar scan that works for the A6.

I can check what happens if I leave the cap open or block it on an A6 4F.

Best regards, Rainer.

Hi,

I was just in the garage, and my 4F doesn't have any sensors in the fuel filler cap. The actuator only has a positive and negative terminal.

I then searched the Audi manual for the 4F model to find information about the entire comfort control system.

- The fuel filler door is not monitored; it only has a servo motor for the locking pin. Limit switches are not monitored; only one motor is powered, and it can be either fully on or fully off.

However, in the US models, there is a different fuel filler neck that has a built-in monitoring system for the fuel cap threads.
This sensor is not installed in the RDW.
The central control unit for the comfort system (J393) expects this signal, but it is currently being incorrectly encoded (or it may be a function that includes this sensor in its BIT allocation).
"In the absence of the installed sensor, the "Close fuel cap" error message will be generated in the FIS (multifunction display)."

As far as my research goes, I can't tell you anything specific about the exact coding, as that always depends on the equipment and software.

would try to investigate the factory coding to narrow down/fix the error.

Regards, Mpire.

Hey everyone.
Does anyone have a schematic diagram for this control board? (see photo).
The idea is to check where the fuel tank cap sensor is connected and potentially short-circuit the pin to help diagnose the problem.
Thank you all again.

So, the car's odometer shows over 150,000 kilometers. Even for someone who uses it frequently, it takes a few years to build up that level of familiarity.

Has the car had this problem since it was delivered? Or when did it start, and what work was being done at the time? Before I start messing with the connectors, I would begin by looking for the root cause in the code.

Hey everyone.

Attached is the coding for the comfort system.

Address 46: Comfort System
Label file: 4F0-910-289.lbl
Part number SW: 4F0 910 289 B, HW: 4F0 907 289 B.
Component: Comfort Device H22 0170.
Revision: 01700022 Serial number: 01021141940000
Encoding: 8315407
Operating number: WSC 02325 785 00200
VCID: 295FBAC5806BD90C56-807C

No error codes found.

Is the company registration number correct? Does anyone know?

Hi, the operating number doesn't matter, as it is configurable.

Hey everyone.
"The problem was identified as a mass defect or oxidation on pin 28 (blue connector) of the comfort control module located in the trunk." For further inquiries, please contact me.
Thank you all for your interest.

Thank you for the feedback!