Self levelling xenon fault

[Spelly]

I have a problem with my xenons on my 03 Gsi
They dont level up on start amd the amber warning symbol in on in the display on my dash
I have read the fault code and found...

B3415 (02) FRONT / REAR CAR LEVEL SENSOR VOLTAGE SUPPLY LOW VOLTAGE

Can anyone explain what this means and which part i need to replace
Im assuming i have a faulty sensor or control unit but want to be sure before spending £££££

youe help is much appreciated


B

[Spelly]

Following on from the above post i have now replaced the headlight level control unit and this has removed the above code
However the light is still on and i now have a fault code of

B1001 46 VARIANT CODING NOT PROGRAMMED

Do i need to program the unit to the car or something
If so, how do i do this using some pc based diagnostics

Thanks