Hi new to the forum but desperately hoping someone has heard of this problem.
Our A6 (3.0 bi-tdi 313hp, quattro, 8 speed auto gearbox) first showed problems when reversing into the driveway one evening. The electronic handbrake came on and the dashboard said there was a problem with the gearbox selection and asked us to select park then select the gear again. After 10-15 minutes of creeping back a foot at a time we parked up.
Mechanic had a look at the codes and couldn't explain it. Got the RAC out and they suggested the issue was the boot sensor as it thought the boot was open. Hold the button for 3 seconds to reset and it would work again. Took it to the garage to replace the sensor but they couldn't get the same error and the car drove faultlessly. They suggested that the gearbox ecu might need replacing at a cost of £4k...
Drove around for a few days without issue, then on the way home the gearbox would move to neutral whilst underway (the gearbox selection on the dashboard would disappear) then back into the gear it had been in.
Since getting home sometimes the car won't start but if it does it won't let you out of park and every error you can think of appears on the dashboard; start stop system, tyre pressure sensor system, handbrake system, etc... And the engine management light is on. Also, you can hear stuff happening below the gear selector as if its trying to either free it from Park or select something. Oh, and the electric tourneau cover no longer operates.
I tried charging the battery to see if low voltage was causing a problem but it isn't that.
Has anyone heard of this before or could point me in the direction of someone who can.
Apologies for the length of the the post. Just praying someone can help