Transmission fault

[madden]

Hi all,
D4 MY2011 with 150k on the clock. Towing a 3.5T caravan for 100k with no problems. Gear box flushed at 60k, 90k and at 120k with zf oil. While towing the van into headwind recently in auto and sitting in 5th, the gear changed into 6th, instant fuel indicator froze at 17.2 l/ 100 and car started to slow down. Pressed accelerator to the floor, no response initially but then response and gear shifted to possibly 2nd then yellow triangle, transmission fault. Stopped, switched off/on, warning cleared and went on our way. This is starting to happen often, and especially travelling on uneven roads, now, so can anybody shed some light on possible causes?
Cheers

[shack]

Hi all,
D4 MY2011 with 150k on the clock. Towing a 3.5T caravan for 100k with no problems. Gear box flushed at 60k, 90k and at 120k with zf oil. While towing the van into headwind recently in auto and sitting in 5th, the gear changed into 6th, instant fuel indicator froze at 17.2 l/ 100 and car started to slow down. Pressed accelerator to the floor, no response initially but then response and gear shifted to possibly 2nd then yellow triangle, transmission fault. Stopped, switched off/on, warning cleared and went on our way. This is starting to happen often, and especially travelling on uneven roads, now, so can anybody shed some light on possible causes?
CheersSometimes a "transmission fault" is not really a transmission fault.

I only have a D3 but every time we have had a transmission fault, it was something else which caused the fault.

The last time it was the HPFP.

Usually if a transmission fault appears, it pays to read the engine faults, as that could be at the root of it all.

[BradC]

Usually if a transmission fault appears, it pays to read the engine faults, as that could be at the root of it all.

Pays to read the transmission fault too, because if it's a cascade related fault it'll be something like "stopped receiving data from ECU" or the like.

We don't have a transmission, but from memory the HPFP faults caused terrain response, transfer case and park brake faults. Oddly enough, if I power cycled the car as soon as the first "bong" went off (key off, key back on), it'd reset before the other modules had time to notice the ECU had stopped speaking and it'd just keep going. Probably can't do that with a D4 though.

The D3 manual says this :
When limp home mode is active, the gear position indicator will show one of the following letters which defines the fault
type:

'F' - transmission is operating in limp home mode
'H' - transmission has reached overheat threshold temperature and transmission is operating in limp home mode
'E' - CAN bus is off and transmission is operating in limp home mode.

[shack]

Pays to read the transmission fault too

Naturally..... Yes, read that as well.

And of course, the dash saying it has a transmission fault doesn't actually preclude it from really having one!!!