Transmission fault

[lt8x7]

To start with I am new to these forums having owned my D3 SE TDV6 for 3 months and I have been a regular reader but as of yet not a contributor.

I bought my D3 second hand with 60000 km on the clock and with a 2 year extended warranty.

I returned it to the dealer recently with a few faults including the transmission changing down to 1st with a clunk. The dealer said that they flashed a newer transmission software and that this fixed the problem.

This past weekend I went on a trip with 3 mates and a boot full of gear. When I pulled out to overtake a car on a hill and put my foot down, a transmission fault came up, HDC fault, suspension lowered, park brake fault etc. and the car basically shutdown with only enough engine power to just make it to the side of the road - not fun.
I switched off the engine, removed the key for a minute and restarted the car. All faults went away. At the next hill, when putting my foot down, the transmission kicked down and then all the faults happened again. Another restart, and we were on our way again.
I drove the rest of the way in "manual mode" and didn't get the faults again.
On our way back form the weekend away, I again drove in manual mode and all seemed well, until at a particularly steep hill, I put my foot down to get past a car with the car in 3rd gear. As the power came on, the faults happened again and I was left struggling to safely get to the side of the road so I could restart the car.

It seems that when the torque level gets above a certain level, the transmission "fails".
Prior to the software update, this never happened.
How could the software update cause this?

I will be paying a visit to the dealer on Tuesday.

[jonesy63]

Root cause is possibly a faulty brake switch. It is a cheap part (XKB500110 - $28 from a dealer). I carry a spare now, having had this on my 3 month old D4.

I hate the "lowering for your safety" message that pops up - not what you want when offroad! :mad:

[lt8x7]

I took it to the dealer today.
They say the high pressure fuel pump needs replacing. They say that the pressure is well below spec. It is getting replaced under the extended warranty.
I asked how this could bring up the transmission fault, which is the first fault to display and they said that it WAS the cause.
I asked if the brake switch could also be "the cause" and they said they had tested it and the switch was fine.

A question to the masses:
Should the break switch be so sensitive that if I breathe on the pedal it activates?

[lt8x7]

Picked it up yesterday and it seems to be driving better.
The dealer refused to look at the brake switch. I think I will buy one as an emergency spare to keep in the car.