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-   -   Xenon self levelling warning light (https://forum.a8parts.co.uk/showthread.php?t=16510)

wibly 3rd December 2021 05:54 PM

Xenon self levelling warning light
 
I bought the Santorin blue S8 from member smoothcoupe back in March having wanted one since seeing a group of them competing at Wiscombe hillclimb back in 2006 or 2007. Lovely car and I am slowly fixing some minor issues and cosmetics. Recently I had the front headlight level sensor arm come adrift triggering the warning light and giving the following fault codes from my OBDEleven :-

55 Headlight Regulation

System description: dynamische LWR D04
Software number: 4B0907357C
Coding: 00001

Trouble codes:
00776 - Left front level control system sensor Short circuit to B+
Intermittent
01533 - Terminal 56 (lights for headlights) Open circuit
static

I made up a replacement rod with some 6mm threaded rod and a couple of ball joints and tried to clear the fault codes, 0776 has gone but 01533 won't clear and the warning light is still on, a friend with full VCDS has tried to clear it and reset various things but the fault and light are still there. I've just checked back and 01533 was there back in July before the sensor problem.
The headlights all work and the levelling motors function if I test them with the OBDEleven, I've had the bulbs out (Osram D2R & generic H7s) and can't see any obvious wiring problems so am a bit stumped and need to get rid of the warning light to pass the MoT. I have read the various previous threads but couldn't find anything similar, has anyone had this fault code before and found a solution ?

David's8 4th December 2021 06:15 AM

1 Attachment(s)
I cant offer any suggestions but i attach the D2 wiring diagrams which might help you in the search.

Ronin 4th December 2021 10:06 AM

Start with replacing fuse 56
then replace the sensor if both codes are still present
once the sensor is replaced you will probably have to calibrate them, I used vcds lite for it

HPsauce 4th December 2021 10:19 AM

It does nonetheless sound like two probably separate and unrelated problems. Ore one in the wiring.
Fuse 56 probably covers both the level sensor and lights so there appears to be a relationship.

MikkiJayne 4th December 2021 10:49 AM

Conter-intuitively, terminal 56 has no relationship to fuse 56 - its a psuedo-arbitrary number which Audi use for 'headights on'. It comes from the light switch, powers both headlights (via fuses), and goes straight in to the level controller without going via a fuse. If the headlights come on then, barring a wiring fault in the cabin, there has to be power to that terminal. The level controller is powered from fuse Yellow 1, but if that was blown you wouldn't be able to talk to it with OBD11.

I have seen a bad level sensor cause a supply voltage fault to be recorded in the level controller. The wording in VCDS is different, but this may be the same issue.

Also worth noting that the arm coming off doesn't normally cause a short circuit code - thats an electrical failure in the sensor or a corroded terminal on the sensor connector. Usually the arm off will cause an implausible code as the control unit sees an impossible signal from a working sensor.

I'd change the front sensor and see how it behaves. The Febi unit is OE and is cheap enough not to waste time with the Chinesium version.

wibly 6th December 2021 08:19 PM

Many thanks for your replies Terminal 56 is the DIN number for the supply to the headlights with 56a being high beam and 56b low beam, in my experience with Porsche and VW it is always labelled on the light switches and relays.

I have checked out the front and rear level sensors and both appear to function correctly, terminal 1 has a good earth, terminal 5 has a 5 volt supply and terminal 4 varies with the position of the arm and gives 2.5 volts with the arm lined up with the plug socket which appears to be the at rest position.
I read elsewhere that with the dipped beam switched on moving the arms should move the lights up/down, unfortunately this doesn't happen with either sensor. Could it be the headlamp control module ? Where is it located ?
I am still getting the 01533 Terminal 56 error code and warning light, I did notice that the warning light is there immediately I select reverse but if I leave it in gear and turn the ignition off and on, for a couple of seconds I get an OK then the headlight warning light returns, could it be a calibration issue ?
Any suggestions gratefully received.

steamship 7th December 2021 12:33 PM

1 Attachment(s)
Quote:

Originally Posted by wibly (Post 167861)
Could it be the headlamp control module ? Where is it located ?

This may be what you're looking for (number 1 in the attached image). It's the headlight range control unit which I assume deals with the self levelling. As to it's location, it appears to be at the base of the B-pillar, so presumably behind the trim. EDIT: That should be passenger side (RHD) B-pillar.

http://forum.a8parts.co.uk/attachmen...1&d=1638883503

HPsauce 7th December 2021 12:56 PM

Out of interest I did a bit of "Googling" and a lot of similar issues seem to relate to the wiring to the headlights, especially poor connections at the lights themselves.
Might be worth undoing all the connectors and ensuring they are dry clean and free of corrosion.


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