Hi, wondering whether anyone has experienced this? Got a T6 Kombi Highline which is lovely but...... it has an annoying habit of reducing power momentarily when driving downhill whilst also turning (either right or left it doesn't mind but it has to be more than a mere bend). We mentioned it to the VW garage when it had it's first service but they couldn't replicate it. So generally the bend is tight enough to have lifted off power but not sufficient to be braking, usually we are in 3rd. It never cuts out completely, although it did this morning but I think that was the stop/start problem I have read about on this forum separately and I believe it to be unrelated to that specific issue.
I go over a steep hump back bridge regularly, where i have a little right hand lock on, and it always shuts down momentarily, and then thew power comes back. Its normal i believe, my old vw did it as well. I imagine it is to shut the engine down in the event of a crash, or losing control.
Nope haven't had such a problem, but it can't be safe, lose your engine on a downhill bend = no brakes and no steering! I would not be chalking that one up as a safety feature. It's the opposite. If mine did that I'd be dumping it back at the dealer's.
Thank god for that.
Mines the same. I thought it was charging the batteries when rolling and easing off the throttle ? It does it at exactly the same spots every time ?
Nope. 6 speed 4 motion .
I made a comment about this when i had my loner 140 manual 4motion. As Dave said same place every trip , sharp dip down a lane i travel home on some days. Very wEird 
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Or even weird, Studley.I made a comment about this when i had my loner 140 manual 4motion. As Dave said same place every trip , sharp dip down a lane i travel home on some days. Very wired
So speed is likely to be between 20 and 25mph, the specific bend where this occurs for us is tight so we have lifted off the power, probably almost entirely but generally because we know the route so well have adjusted our speed sufficient to not be braking. We would never be going steady with acceleration as its also down hill immediately after the bend. And yes 4-Motion.
Thanks. I’m not sure if we have a match. I see some similarities, but… Anyways, here is my story.
I have been experiencing a kind of feeling of momentarily losing control doing light turns - pretty much same way as you do. Easing up the pedal into a bend just to get through without braking. Usually slightly downhill. Definitely no extreme maneuvering, or on the edge of friction driving, just to go smoothly. The speed range of my observations has been 20-40 mph (30-60km/h)
Sometimes in the turn the van suddenly makes the turn more sharply – a kind of jump inwards of the curve- On left turn, steeper left. On right turn, steeper right. So, my first thought was there had to be oil on the road and the car slipped and then regained the traction. Happened a few times and then the van started to be a kind of reluctant to turn (at that speed range) and even had some strange vibrations.
Took it to service and they spend quite some time checking things, and eventually/fortunately they decided to check also oil in Haldex-clutch (4-Motion clutch). The van had only 13.000 km (8000 miles), scheduled Haldex oil change way ahead, in 60.000 km. They even saved the oil for me to have a look. The technician said it is way too black for those km’s, and had a smell of burned clutch.
After those actions van returned pretty much back to normal. That was in November. But, I still wasn’t totally happy so also wheel alignments were checked later – but nothing there. In January I hooked a VCDS-recorder to Haldex-unit, and it looked like that the clutch gets locked too hard when it is not supposed to do so – it is definitely supposed to get released when you take your foot off from pedal. So, theory now is that the clutch locks front and rear axles (for unknown reason), and if the release happens when I’m turning that certainly makes me feel uncomfortable. The service technician hooked their tester to verify my observations – and, as expected, they show the same, so the data is and has been available at VW’s problem resolving center some time now. We also did a run with another T6 4-Motion to verify the correct and assumed operation of 4-Motion - very different.
It was seen that on mine clutch is locked every now and then (several minutes interval) for a few seconds (2-20s) up to 100%, and then released suddenly. When this happens when driving straight it is not noticeable. But when turning, for sure. Still just a theory but evidence is pointing to that direction...
So, the case is still open. Possibly burned Haldex-clutch, and definitely non-functioning 4-Motion. Or, actually too eagerly operating 4-Motion. A lot of symptoms but root cause unknown still.
If you would like to experiment, it can be done just by removing fuse SC33 (engine/ignition off). Be aware, that besides 4-motion it shuts down also ESC, ACC, Front Assist, Start-stop, tyre pressure monitoring and rear differential lock - so it will be a nice light and warning tone show
And bunch of fault codes for your serviceman. Just record the mileage so they don't need to dwell on these ones.
Would like to hear your thoughts.
EDIT: Deeper analysis
www.t6forum.com
I have been experiencing a kind of feeling of momentarily losing control doing light turns - pretty much same way as you do. Easing up the pedal into a bend just to get through without braking. Usually slightly downhill. Definitely no extreme maneuvering, or on the edge of friction driving, just to go smoothly. The speed range of my observations has been 20-40 mph (30-60km/h)
Sometimes in the turn the van suddenly makes the turn more sharply – a kind of jump inwards of the curve- On left turn, steeper left. On right turn, steeper right. So, my first thought was there had to be oil on the road and the car slipped and then regained the traction. Happened a few times and then the van started to be a kind of reluctant to turn (at that speed range) and even had some strange vibrations.
Took it to service and they spend quite some time checking things, and eventually/fortunately they decided to check also oil in Haldex-clutch (4-Motion clutch). The van had only 13.000 km (8000 miles), scheduled Haldex oil change way ahead, in 60.000 km. They even saved the oil for me to have a look. The technician said it is way too black for those km’s, and had a smell of burned clutch.
After those actions van returned pretty much back to normal. That was in November. But, I still wasn’t totally happy so also wheel alignments were checked later – but nothing there. In January I hooked a VCDS-recorder to Haldex-unit, and it looked like that the clutch gets locked too hard when it is not supposed to do so – it is definitely supposed to get released when you take your foot off from pedal. So, theory now is that the clutch locks front and rear axles (for unknown reason), and if the release happens when I’m turning that certainly makes me feel uncomfortable. The service technician hooked their tester to verify my observations – and, as expected, they show the same, so the data is and has been available at VW’s problem resolving center some time now. We also did a run with another T6 4-Motion to verify the correct and assumed operation of 4-Motion - very different.
It was seen that on mine clutch is locked every now and then (several minutes interval) for a few seconds (2-20s) up to 100%, and then released suddenly. When this happens when driving straight it is not noticeable. But when turning, for sure. Still just a theory but evidence is pointing to that direction...
So, the case is still open. Possibly burned Haldex-clutch, and definitely non-functioning 4-Motion. Or, actually too eagerly operating 4-Motion. A lot of symptoms but root cause unknown still.
If you would like to experiment, it can be done just by removing fuse SC33 (engine/ignition off). Be aware, that besides 4-motion it shuts down also ESC, ACC, Front Assist, Start-stop, tyre pressure monitoring and rear differential lock - so it will be a nice light and warning tone show
And bunch of fault codes for your serviceman. Just record the mileage so they don't need to dwell on these ones.Would like to hear your thoughts.
EDIT: Deeper analysis
[T6_measured] 4motion Abnormality And Subsequent Failure
Reference documents: VW Self Study Programme SSP 561 –The T6 2016, which in chapter Power transmission (p.26) for details on 4Motion control logic refers to: VW Self Study Programme 414 – 4MOTION with 4WD coupling generation IV. The document can be read and downloaded at SSP 414 Spesifics...
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between this and the issues with the Adblu on the 150Dsg I'm wondering what I'm buying into here!!!
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