Electric Tailgate / Trunk stopped opening with key 2017/18 T6

[Mark Peo]

Hi, wondering if anyone would have any ideas why the electric tailgate would have stopped opening with the key. I have already searched and appears that some people had resolved the issue as they were parked too close to something but that isn't the case here.

It stopped opening a while back now, nothing parked around the van and tried all 4 keys that came with the van. It has electric sliding doors left and right so the button is on the side of the key. On a long press of the button the indicators flash so I know it's getting a signal to open but nothing. This is what it would do if you were parked too close to something and the sensors stopped it opening. The tailgate will still open when the handle is pressed and will close on the button mounted on the tailgate

I did have an issue with park pilot a bout 2 months after the tailgate stopped opening with the key. Turned out to be some water on the front park sensor connector to the bumper as diagnosed with VW during a service. After this was resolved the tailgate still failed to open with the key.

Following that a rear park sensor failed so that was changed and still the tailgate will not open with the key and on long press to open the indicators still flash.

Done a scan with VCDS and nothing obvious that I can see but I'm no expert. Seems like the signal received from the key isn't activeting a signal to the switch on the tailgate?

Any help or ideas would be appreciated. Thank you in advance

 

[Kind of Blue]

2019 Caravel 4Motion, I do not know about no longer opening, I do not believe that mine has ever opened with the key,

 

[Pauly]

Can you post a full vcds scan ?

 

[Mark Peo]

Can you post a full vcds scan ?

Hi Pauly,

just scanned and have 2 faults show below. Hopefully attached ok.
Starting to think there may be a cable issue although the van is not converted in any way.
The fault in central electric is for the rear right door, i have left slide, right slide (both electric) and rear tailgate.

• 09 cent. elec
• 19 Can Gateway

Thanks for having a look

cheers

 

[Mark Peo]

Can you post a full vcds scan ?

Hi Pauly, did you get a chance to cast an eye over the scan?
Cheers

 

[Pauly]

The 09 fault I think it’s spurious, it’s more for info than a fault but the gateway fault is interesting, not one I’ve experienced before

Personally I think I would clear all the codes and see what returns, if the gateway fault comes right back then I guess it would mean a linbus fault that would need to be investigated

 

[Wasbeer]

Not helping, but I have the exact same problem for about a week
First, the key fob didn't work, and the button inside the car to open the tailgate also stopped functioning.

The tailgate still opened automatically when using the handle. I only had the issue that it wouldn't close automatically with the button after the 10th time or so — I had to push the tailgate down manually. After doing that a few times, the tailgate stopped opening automatically with the handle as well. So, it went from working perfectly to not working at all in about a week.

I don't have VCDS, but if anyone has suggestions on what to do, I'd gladly try your solution.

Thanks in advance!

 

[Mark Peo]

The 09 fault I think it’s spurious, it’s more for info than a fault but the gateway fault is interesting, not one I’ve experienced before

Personally I think I would clear all the codes and see what returns, if the gateway fault comes right back then I guess it would mean a linbus fault that would need to be investigated

Thanks Pauly, cleared faults, rescan and still there.

Any suggestions on how to investigate Lin bus fault to the tailgate?
Cheers

 

[Pauly]

I guess i would start with the wiring diagrams to see what linbus cables you have in the van and go from there but im not 100% that its related to the tailgate as dont recall any linbus involvement in that control module ??

 

[Mark Peo]

I guess i would start with the wiring diagrams to see what linbus cables you have in the van and go from there but im not 100% that its related to the tailgate as dont recall any linbus involvement in that control module ??

Thanks
looks like I'll have to do a bit more research and try get a hold of wiring diagram for the van

 

[Pauly]

All the wiring diagrams are in the downloads section but it does require VIP membership to access a lot of that content

Let me have a look and see what i can find for you

 

[Pauly]

Just having a look through the databus network chapter from the wiring diagrams

T6 - Data Bus Network Wiring Diagram

Circuit Diagrams for the Data Bus Network Covers all wiring between control modules on the drivetrain CAN bus and convenience CAN bus, also includes LIN bus wiring Please check the history/updates tab, first release is for early T6s...

www.t6forum.com

the only linbus wiring i can see does not relate to the tailgate







The tailgate (rear lid) control module is connected to the canbus circuit just like the majority of the control modules in the van

 

[mmi]

-------------------------------------------------------------------------------
Address 19: CAN Gateway (J533)       Labels:. 7E0-909-901.clb
   Part No SW: 7E0 909 901     HW: 7E0 937 090 C
   Component: GW-K-CAN TP20 H82 0752 
   Revision: B9082001   
   Coding: 042307
   Shop #: WSC 02739 534 130884
   VCID: 68D541689B8940D663-803C

1 Fault Found:
00470 - Company Comfort Databus in Single Wire
            012 - Electrical Fault in Circuit - Intermittent
             Freeze Frame:
                    Fault Status: 00101100
                    Fault Priority: 2
                    Fault Frequency: 6
                    Reset counter: 181
                    Mileage: 0 km
                    Time Indication: 0
                    Date: 2019.06.19.
                    Time: 13:08:06


-------------------------------------------------------------------------------

The unit "J938 Rear lid power opening control unit" is on convenience CAN bus (the bus reported to be at fault - labeled as Comfort Databus in VCDS scan)

 

[Pauly]

It seems i made a mistake and took single wire to mean linbus

Based on the above, a control module requires 4 wires to be able to communicate, a power pair (+ve and -ve) and a canbus pair (can high and can low)
I would probably start by getting at the control module in the rear quarter panel and checking for water ingress in that area and also disconnect the 3 plugs that connect to the module and make sure they are all clean and plugged in properly

 

[Mark Peo]

It seems i made a mistake and took single wire to mean linbus

Based on the above, a control module requires 4 wires to be able to communicate, a power pair (+ve and -ve) and a canbus pair (can high and can low)
I would probably start by getting at the control module in the rear quarter panel and checking for water ingress in that area and also disconnect the 3 plugs that connect to the module and make sure they are all clean and plugged in properly

Thank you for looking. I’ll try get a look during the week. Do you know if nearside rear or offside rear?
Cheers

 

[Pauly]

T6 = NSR
T6.1 = OSR

 

[mmi]

I think the above is just for J605 Rear lid control unit

Then the box connecting into convenience CAN bus on T6

 

[Pauly]

That picture is a 6.1

 

[mmi]

I'd like to disagree - T6.1 doesn't have J938 - only a single box J605, and yes, in that location. And, has only two connectors.
The snippet was from a fairly old diagram - well before T6.1

 

[Mark Peo]

I'd like to disagree - T6.1 doesn't have J938 - only a single box J605, and yes, in that location. And, has only two connectors.
The snippet was from a fairly old diagram - well before T6.1

View attachment 273295

Thanks mmi. I did get chance to look on the nearside yesterday and there were only the sliding door control modules below the motor. I'll hopefully get time today or tomorrow to look at the offside, I need to remove a fixed in box first to get access. I did take the cover off for the sliding door motor and can see a module mounted lower down. From what I could see it looked dry in there.