Self Levelling Suspension Fault - Locked Suspension Yelow Warning on Dash

[ceilidhalfie]

Hello folks. Went this morning to reverse the car out of the garage. Reversed about 2 feet when the above warning symbol appeard on the dash of my 2002 Audi Allroad AKE Automatic 2.5TDI. Switched off/on and symbol still there.
So, got the laptop out and ran diagnostics and sure enough there were a couple of DTIs Cleared all the DTIs and switched off the ignition. Switched on ignition and fault reappeared. Started engine fault still there. Re-ran diagnostics and again got the following DTIs:

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Address 34: Level Control Labels: 4Z7-907-553.lbl
Part No: 4Z7 907 553 E
Component: - 2C1A1 D040
Coding: 25500
Shop #: WSC 09999
2 Faults Found:
00774 - Level Control System Sensor; Left Rear (G76)
57-00 - Electric Circuit Failure
01771 - Control Module for Headlight Range (J431)
79-00 - Please Check Fault Codes
-------------------------------------------------------------------------------
Address 55: Xenon Range Labels: 4Z7-907-357.lbl
Part No: 4Z7 907 357
Component: dynamische LWR D07
Coding: 00030
Shop #: WSC 02325
1 Fault Found:
00774 - Level Control System Sensor; Left Rear (G76)
31-00 - Open or Short to Ground
-------------------------------------------------------------------------------

I then jacked the car up, removed the left rear wheel and removed the electrical connector to the left rear level sensor. Cable, connector and terminal all looked ok. So I am thinking, just like the right rear 4 years ago, the left rear sensor has now packed in.
If so, no problem, I can order/fit a replacement.

However, before I do this I thought I would just first check with you folks. Two weeks ago I replaced both my very cloudy headlights and have since done over 500 miles (including night driving) with them. When I fitted them, absolutely no problem with the range sensor motors in each headlight.


So, what are your opinions - just co-incidence and looks like faulty level sensor OR is there more to it?
Again, many thanks for your continued support.
John

Just been checking the service manual and cam up with the following info:
General notes
Differing automatic headlight range control systems are fitted in the Audi A6:
t Automatic static headlight range control on all vehicles with gas discharge headlights (excl. S6 and A6 allroad) up to model year 2000.
t Automatic dynamic headlight range control on S6, A6 allroad and A6 from model year 2001 onwards.
Function
t The automatic static headlight range control system corrects the angle of the dipped beam only at the start of a journey and when the vehicle is stationary.
The automatic dynamic headlight range control system additionally maintains a constant dip
t angle when the dipped headlights are switched on and the vehicle's inclination changes due to acceleration or reduction of speed.
One level sender each at the front and rear axles signals the compression of the vehicle
t suspension in both headlight range control systems. A signal proportional to the running speed is additionally processed.
t The control unit evaluates these signals and actuates the headlight range control motors with dipped beam switched on.
t Drivers are made aware of system faults by way of a warning symbol in the centre display of the instrument cluster.
Components of automatic headlight range control system: 1 - Headlight range control unit -J431-
2 - Rear left vehicle level sender -G76- 3 - Front left vehicle level sender -G78-
- Left headlight range control motor -V48-
- Right headlight range control motor -V49-
　
So, looking at the following extract of the fault table, it looks most likely that the sensor IS faulty (and also I cannot use current flow diagrams if my life depended on it!).

Display on -VAS 5051-	Possible cause of fault	Fault elimination
00774 Rear left vehicle level sender - G76- t Open circuit/short to earth t Short to positive	Open circuit or short to t earth/positive in wiring to component	– Use current flow diagram to check wiring and connectors
t Rear left vehicle level sender -G76- defective	– Renewrear left vehicle level sender -G76- →Rep.Gr.42

　

[bagpipingandy]

HI,

it is only the left front sensor which deals with the headlight range, i assume it has just flagged up the error code as the module 34 has the issues

before changing the sensor, pull the rear bench seat up and check the connection under there, their is a join plug under that bench going to the to the rear level sensors one each side, check it is not corroded

if it looks good you can do a continuity check to the rear plug or you could swap the rh and lh sensors to see if the fault moves to narrow down if it is the sensor or wiring issue

let us know what you find

regards

Andy

[fjsmits]

Hi also check behind the front wheel. I'm not sure which side it is on in the UK but in Sweden it is on the LH side (drivers side) and make sure that the arm at the front and rear are not broken or dislodged.

[ceilidhalfie]

Well folks I decided to take the easy option and replaced the left rear sender with a NEW one. So, now £100 out of pocket and I am no further forward - same errors after I cleared DTCs and started the car. Also, as this error is still present, VCDS would not allow me to perform the basic adaptation (required after changing a sensor) - When trying to read channels 1-5 I got "ERROR" where level heights should be. So I had to quit the task. Fortunately, Level2 heights seem ok and I can go thru levels 1-4 and back no problem.

Now having found an Audi tutorial on how to read wiring diagrams, I came up with the attached for my 2002 Allroad.




As you can see from the attach wiring diagram, G76 Rear Left Sender is used in Automatic dynamic headlight range control on S6, A6 allroad and A6 from model year 2001 onwards. Before 2001, STATIC dynamic headlight control was used and I THINK, with this only the front left sender was used.

So, having looked at an earlier (2009) post on this forum, I was going to remove the rear seat and open the T4ao 4-pin black connector.
Step 1) I would put a multimeter between T4ao/1 and T4ao/3 (on the Halogen control module side). With the ignition turned on, I should get a reading of 5 volts. If so, this would prove the J431 and circuit were ok. If not, on to Step2. Otherwise, run continuity check back to left rear sender connector.
Step2) I would open up the bottom right A-pillar trim and open up the T10aw 10-pin black connector. Connect the multimeter accross T10aw/8 and T10aw/9 terminals and repeat voltage test. If test unsuccessful Step3. Otherwise run continuity check betrween T10aw and T4ao.
Step3) Run continuity check from T10aw back to J431 connector - if ok, fork out another £30 or so for a used J431 Halogen Control Module.
That is my plan, and woul really , really appreciate any input from you folks - ESPECIALLY...
ANDY - how do you remove the blasted rear seat. The manual says lift seat straight up off the clips on either side and pull out. Well, my wife and I have tried - left and right sides seem free to come but the centre (above and slightly back from the two drink holders) feels like it is bolted down. I am scared to use brute force in case I break something - including my double hernia (not kidding here folks - waiting to go under the knife!).
So I am stuck until I can get the seat out. Why is EVERYTHING on this car difficult to fix? No prises for guessing I am getting somewhat depressed!

[bagpipingandy]

It needs a good hard tug to lift,

get in the car 1 foot either side of the centre, both hands on the lower rear bench at either side of the cup holders and pull upwards as hard as you can, it is 2 big spring clips holding it down, place hands and pull where the resistance is either side of the cup holders

regards

Andy

[ceilidhalfie]

It needs a good hard tug to lift,

get in the car 1 foot either side of the centre, both hands on the lower rear bench at either side of the cup holders and pull upwards as hard as you can, it is 2 big spring clips holding it down, place hands and pull where the resistance is either side of the cup holders

regards

Andy

Thanks for that Andy. King Kong approach tomorrow! What do you thnink about the diagnostics plan? Also, until I can resolve this problem, what about simply disconnecting the connector form the halogen range cotrol module and thus turning the car into a non-halogen control module system - it might let me do the basic adaptation??

[bagpipingandy]

DO NOT attempt the adoption at all if their are any fault codes stored, the car must be able to get to level 2 with no fault codes stored, we need to fix this fault 1st, my shot would be that T4ao 4 pin plug under the bench, check it for corrosion or any signs or issues.

after that get the multi meter out!!

Im off to the pub!!

best regards

Andy

[ceilidhalfie]

Update coming.

[ceilidhalfie]

Hi all. Finally worked up some enthusiasm late this afternoon to revisit this problem. Glad to say I managed to remove the rear seat - those 4 clips were very secure! Spirits raised somewhat when I found a 20p piece amongst all the debris - now only £99.80 out of pocket so far!

Spurred on by this find I started the voltmeter test. The connector under the seat was pristine - no sign of corrosion. I split the connector and with the two probes of the voltmeter - red on the purple/red terminal and black on the purple/black terminal. NOTHING! Then I thought - maybe probes are too thick and not touching the terminals. So after inserting two pins into the connector, I tried again - BINGO, 5 volts every time.

So I think the above tells me that the wiring is ok from the back seat connector all the way to the Halogen Range Control module.

As it was getting dark, I decided tomorrow I will do the same test at the plug to the rear left sender - hopefully there will be no voltage reading. Will also do the continuity test on this length of cabling.

Does anyone know if I can buy a sender plug? I am hopeful to pin the problem down to corroded/broken connections in the plug, but if so how do I fix it? Can it be broken open and repaired?

[bagpipingandy]

Yes the plugs should come appart but you need a tool to remove the pins, you can use the part number on the plug to buy a new one, but it is just the plastic housing you get, the pins come seperate and you would need to splice them if you wanted to change the pins, they are not expensive

it is the front left sensor which controls the actual headlight height but i think the fault code in the headlight range module is just Acknowledging their is a fault in the suspension system, the headlight range fault will clear when you fix the issue with the rear left,

let us know if it turns out to be a bad connector or other

regards

Andy