Help in diagnosing xenon range control required
 

So I've had errors 0774 and 0776 since purchasing the car, so I tried to fix it by following this http://forum.a8parts.co.uk/showthread.php?t=12058 thread to renew the harnesses which I've succesfully done but after resetting the errors and going for a drive, the errors immediately come back.

Should I replace the sensors next or maybe the headlight aim control module? Is there a way to further test the output of each module? I'm really not sure how to tackle this...

Replace the sensors. They're the same on B5 A4, C5 A6 / Allroad and 8N TT so plenty of them about. Aftermarket sensors often come with the link arm which obviously doesn't work on the D2, but the sensor itself is the same.

Ymmv with Chinesium versions of course.

Will do. Thanks Mikki.

Update:

Yes it was the 2 xenon position sensors. After I replaced them I didn't even need to clear any codes it vag com :)

Update 2:

After about 30mins of driving the error came back, and comes back anywhere between 15 to 30 minutes of driving.

So far I've changed the 2 modules and re-did all the wiring.

Could it be the cheap chinese modules? The thing is once I replaced the sensors the error on dash cleared itself so they were obviously detected and worked for a little while.

Update:
I eneded up replacing the sensors yet again, with Febi units. Now im getting the
'01539 headlights not adjusted' error, but the two previous errors have now gone.
Have I got the levers wrong or something? Or do they need to some kind of calibration? the voltage between front and rear sensors are way off.

You need to do basic settings to calibrate it.

Hmmm, VCDS Lite doesn't seem to support this option. I may have to get the proper full version to do this :(

Full Version of VCDS also shows basic settings as unavailable.
I think this is because the voltages on both sensors are out of range which is 1.7 to 3.5V.

I made sure the new arms for the new febi sensors were exact lenght, and at the time of VCDS measurement the car was at a large Morrisons car park, so the ground was really really flat. Very strange.
I'll try adjusting the lenght of the arms (which will adjust the volrtages) next i think...

Is it lowered? That causes problems with the basic settings. I have to pick mine up on the lift a couple of cm before it'll calibrate