2008 A6 Allroad - suspension dropped on one wheel and lights flashing

[jr92897]

Hi, I've just bought a 2008 A6 Allroad 3.0 TDI Auto with around 190k.

A green suspension light (down arrow) came on and the car felt like it was slanted to the left. I had a look and the rear left of the car had sunken and the wheel was about 1cm from the arch but not rubbing. I got home and the front left one had also sunken but the other two appeared fine. I checked out the suspension settings and sometimes nothing would happen when changing settings and other times I would hear something whirring and feel a little clunk but the suspension wasn't actually changing in any way.

I took the car out later on for a pretty essential journey and now there's another light, an amber suspension light (up+down arrows) and both are flashing continously. I called the AA purely for a diagnosis and they said they couldn't connect to the control unit; they weren't getting a response from it. The car was relatively cheap and I'm willing to spend some money on it as it's otherwise sound.

Can anyone shed some light on what the issue is and how much I'd be looking at to sort it? It is booked into a VW specialist later this month but I'm hoping to solve it before then. Thanks.

[54A4Avant]

Generally the first step would be to park the car overnight with “jacking mode” switched on within the MMI screen. This disables the self-levelling function, so that if the problem is a leak in one corner then that becomes apparent when you return to the car the next day and find one corner dropped.

The fix would be to replace the air spring, or find the leaking airline on that corner.

Commonly associated with this is the air compressor piston ring wearing out from all the work the compressor does to compensate for the leak (either keeping the car level, or pumping it back up after it's dropped overnight). So after fixing a system leak, you’ll normally need to refurb the compressor with a piston ring kit from eBay.