My first post here - looking for some experienced answers . . .
I have an issue that is so frustrating: Sometimes, when on the motorway the car goes into limp home mode.

The car:

  • Audit A4 SE Saloon
  • 2.0 diesel 170bhp
  • 2015 – ‘54’ plate
  • Manual (6 gears)
  • 131,000 miles
  • The car has been within the family since new (father in lawand now me)

The issue:
When driving in sixth gear at 70mph the car sometimes goes into Limp home mode (I think that’s what its called), and the coil symbol starts flashing yellow.
It is not a consistent issue and can be prevented by not going into sixth gear and keeping the car fifth gear.
It seems to do it when the car is slightly labouring, for instance when driving okay in sixth on a flat motorway, then starting to go up a slight incline.
It can be cleared by turning the engine off and on again (not safe I know but I do this whilst moving) and it instantly clears the issue and full power is back (minus the cruise control and a few other electrical stuff, which return when you park up and startup again). But the issue will return if I go back into sixth.
It doesn’t seem to do it on the 40 mile journey to work (using sixth gear) but will do it on the way home (figure that out??).
I’ve had the car hooked up to a machine that reads the ECU –probably not a pukka VW/Audi machine but one from ebay and there’s nothing to report.
Does anyone have any ideas why the car would be doing this? Is it something to do with airflow/ gas flow? The reason I’m suggesting this is in sixth gear I would assume the flow is less and perhaps its getting clogged up. I’m mechanically naive so that’s me plucking something from the air . . .
Any help would be very thankful as the winter months are coming up and I need to make sure the car is bang on.