Allroad level control electrical fault

[snugglebum]

Hi guys

Ive been on hols for 2 weeks after replacing the front drivers side air spring. Car has drove and performed perfectly all holiday. However after a 300 mile drive home today the susspension light and hedlight level warning appeared on the dash about 2 miles from home?
The level control works perfectly and i can select all 4 levels. Ive scanned for fault codes with VAG-COM and heres what i get.

VAG-COM Version: Release 409.1-S
Control Module Part Number: 4Z7 907 553 Gºu
Component and/or Version: - 2C1A1 D052
Software Coding: 25500
Work Shop Code: WSC 00495
2 Faults Found:

00776 - Level Control System Sensor: Left Front (G78)
57-00 - Electric Circuit Failure
01771 - Control Module for Headlight Range (J431)
79-00 - Please Check Fault Codes

Am i right to guess its pointing me to a possible bad connection on the front passenger level sensor or faulty sensor?
Im also guessing that the light level system needs the infomation from the sensor too thats why i get the extra fault code?

Ive had a quick look at the connector but i couldnt work out how to remove it? Any ideas? Im bloody knackard after a long day so gonna jack it up and have a better look in the morning.

Cheers
Lee

[snugglebum]

Done a little interwebing and found it could affect the Xenon Range (55)

VAG-COMed it

Control Module Part Number: 4Z7 907 357
Component and/or Version: dynamische LWR D05
Software Coding: 00030
Work Shop Code: WSC 02325
1 Fault Found:
00776 - Level Control System Sensor: Left Front (G78)
31-00 - Open or Short to Ground

From what ive read its prob a faulty sensor?

Im gonna check the wiring in the morning for breaks.

Call me a mechanical moron but left front is front passenger side? isnt it?

Cheers
Lee

[bagpipingandy]

Hi Lee,

yep front left is UK Passanger side, and i believe as you rightly suggest that level switch also controls the auto headlight leveling on the allroad, so hence you have the fault code in the 1st post. it would suggest a fault or brake in the wiring to that level switch but if it has just happened once and it working ok perhaps it was just a hiccup!! .

Andy

[a8 tech]

check the connection first as they are very prone to corrosion and this is most likely causing a resistive circuit /open circuit sporadically and check measured value blocks to see if the height shown by the sensor is obviously incorrect then disconnect the rod and see if the mvb moves when moving the rod up or down.
if the sensor is defective and requires replacement then don't forget to adapt the suspension http://www.ross-tech.com/vag-com/cars/levelcontrol.html

[snugglebum]

Cheers guys!

The fault is constant and wont just clear. I managed to have a quick look at the wiring last sunday but all looked ok. I couldnt manage to get the connector off? Any ideas? Does it have a locking clip or is mine just stuck?

a8tech you say check the measured value blocks, im gussing this gives the level the sensor is at. Can you point me in the right direction of how to do this with vag-com?

Cheers
Lee

[a8 tech]

Yes mvb will show you if the sensor is working by simply adjusting the suspension you should see a rise as the sensor moves,the ross tech label file seems out of action but i will look on my other pc after as i have some info on there for mvb.Back soon

[snugglebum]

Ive just had another look at the connector.....how does it come off? Ive pulled and pushed it as hard as i dare without breaking it.

DSC01901 (1148 x 764).jpg

Any ideas?

Cheers
Lee

[a8 tech]

Squeeze the upper connection and pull and prey.lol
Ok go to headlight range control 55 select mvb 002 for G78 front left passenger side sensor
static the reading should be 1.66 v to 3.45 volt.You can swap senders from side to side to eliminate if unsure then check the wiring for continuity,resistance and mutual shorts
check the wiring purple and yellow and purple and green (connect a voltmeter across these two) with ignition on and you should see 5 volt with the sender disconnected and purple and white is the signal wire which will change with the sensor movement

[snugglebum]

Thanks a8tech for all the info....it guided me to the faulty sensor.

I used VAG-COM to check the voltage from the sensor, it read 0.01v.

I traced the wiring and tested the voltage at the sensor connector, all ok.

The trick i used to test if the sensor was faulty or the wiring was to hook 2 wires to a 1.5v aa battery. I then connected the battery to the sennsor plug. i bared the wires conected to the battery and pushed them into the slots for ground - and the purple/white sensor wire 1.5+.

So - on the battery to ground on the connector and + on the battery to purple/white sensor.

I then re scanned with VAG-COM on means blocks and got a 1.5v reading on the front left sensor. So this reading ruled out the wiring.
Ive managed to get a sensor from Ebay for £15 (£92+VAT Audi). Fitted the sensor today... all working great.

Thanks again a8tech

Lee

[a8 tech]

No problem Lee