rotto

Has anyone else noticed that the soft coding values for the xeon headlight level are not as straightforward as one might expect? Specifically I noticed on my car that value 00010 is the LOWEST possible level while 00020 is the HIGHEST possible level. All the other values are somewhere in between, with the original value of 00060 being the next highest level. This is inconsistent with the write-up at:
https://www.audiworld.com/tech/misc29.shtml

Even more confusing was trying to see the incremental difference between two adjacent values. Many times the level wouldn't change at all when going from 00050 to 00040. But if going from 00010 to 00040 the level would change. Other times the level would change between to adjacent values. It seemed very screwy to me. As far as I could tell I did not have any communication errors with the controller. According to the Bentley manual the VAS 5051 software gives you up and down arrows to make the adjustments. Is there supposed to be some strange mapping between the actual values and the level? Any insight to the matter would be greatly appreciated.<ul><li><a href="https://www.audiworld.com/tech/misc29.shtml">https://www.audiworld.com/tech/misc29.shtml</a</li></ul>

Avant XP

I would like to find something higher than 00060, but not quite as high as 00020. If I read the OFM correctly, the adjustment is supposed to be manual anyway?

rotto

Yes. From what I understand the manual adjustment (using a screw driver) that is referenced in the Bentley guide is to adjust the baseline reference point for the system (the "setting position"). You are supposed to get the lights perfectly aligned at this time and then have the system learn the position so it can maintain the level. There is no mention of software level adjustments after the fact but there is a screen shot of the VAS 5015 screen that shows what look to be up and down buttons for software adjustment of beam level.

I am not certain why there is an option to set a software bias on the reference point. Maybe someone can enlighten us.

Below I have included my findings on the valid values and results of the soft coding:

Value Level Notes
00010 1 - Lowest; Same as lowest test level (Output Test)
00020 4 - Highest; Not highest test level (Output Test brings much higher)
00030 2 - Smidge lower than 60; 30, 40, and 50 all the same
00040 2 - Smidge lower than 60; 30, 40, and 50 all the same
00050 2 - Smidge lower than 60; 30, 40, and 50 all the same
00060 3 - Next Highest; Original setting
00070 3 - Next Highest; Same as 60

rotto

A fellow AudiWorld member stated that he also found similar non-linear behavior on an '03 A4 1.8T Avant. Oddly enough on a '01 TTC 225 the behavior is perfectly linear.

So the questions are:
1. Why the software bias option?
2. Why aren't the values linear for the bias setting on some models?