Self levelling headlight warning symbol

What's the exact image you're seeing? A dipped beam icon with two up/down arrows? If so - that's the auto level feature. This image can be anything related to that system, so be sure to check it with VCDS or some other diag tool.

Most times it's indicating that it has lost its basic setting; this could be due to an attempted learning procedure, that was failed or aborted. Common causes are defective sensors, defective motors, or a too low car. When lowering more than 5cm, it may very well be that the adjustment arm is sending a too low voltage: the calibration process requires at least 2V to save the position; if you're lower than that, it'll read somewhere around 1.4V (mine does that front and rear, on a 60-65mm lowering). It'll think you're bottomed-out on your shocks, so it won't learn the current setting as default.

Anyway, be sure to check for fault codes - they should be in there.

The self levelling system is done through your central electric unit. If all else fails, you can:

1. Disconnect the sensors on your control arm (if you want...)
2. Code your central electric to have auto level disabled ("remove feature")
3. Pull fuse (if required, may not even be necessary)
4. Adjust headlights using your manual adjustment screws (hex 6)

As the system is disabled, it won't adjust anymore. If you code it out of your system, it won't throw an error.

If it is a single motor, be sure to replace it with a motor from a xenon headlight. The regular halogen motors are different (pinout, assuming they lack position sensoring). That can't be too expensive, plenty to find at a breaker, and I might even have a few spares over here...

Let's just start by getting your car checked for fault codes. If it's something simple as re-learning your positions, do it... that's free and easy. Otherwise, post fault codes and/or descriptions.