jgospodaric

Hi,

Allroad C5 2.5 TDI 2002. front left sensor is unstable (00776 - Level Control System Sensor; Left Front (G78) 57-00 - Electric Circuit Failure):

1. checked wiring U pink-yellow pink-green 5V, and everything seams ok
2. replaced with right sensor, it doesn't show error on left side
3. tried to use left on right sensor point, it show again same error on right side

Inside sensor it was not corroded, whole board was heated to resolder. It worked for 10 minutes and after test ride same error showed up again.

Is it possible to replace only sensor body with with 4B0907503A instead
ordering complete 4Z7941285C?

And did anyone had similar which cause was not as in quattroworld.com Forums: Ride height level sensor DIY repair.

Thnx in advance!

BR, Jura.

PaperToast

the sensor itself is the same for all 4 corners
the only difference is the arm that attaches to the sensor

MrKid

Allroad Ride Level Sensor Front Left 4Z7941285C | eBay

John535is

I could not find anyone selling just the sensor new. Even aftermarket I could not find the exact same model so I ended up buying a used one.

Papertoast is correct, all 4 are the same so you can buy any corner, 10mm ring spanner and a 10mm thin open end spanner you can remove the coloured plastic arm.

I also tried the same repair similar to your DIY repair write up but these sensors actually get a fair amount of water, mud, and general abuse so I replaced it.

You may need to do a general height recalibration when all the sensors are working again. There is a good write up on this site for the 402 mod, use that to reset the heights.

You may find your headlight auto levelling alignment has now failed as well. It runs off the front left sensor. You can access it through VCDS, group 55 from memory and you can trigger it to recalibration.

jgospodaric

Yep there is no aftermarket replacement in form of only sensor body for same thing as on 4Z7941285C.

I only see that there is aftermarket replacement for 4B0907503A e.g.:

4B0907503A | eBay

I know that 4B0907503A is used for headlamp range control on non Allroads. But I forgot that Allroads on left side use two outputs from level sensor one for Headlamp Range Ccontrol unit J431 (voltage, analog) and one for self-leveling suspension unit J197 (PWM, digital). Also this sensor body is also interchangeable (e.g. body on 4Z7941285C) but all sensors have this two outputs.

From wiring diagrams for 4B0907503A I see only 3 wires used and as headlamp range control unit is used on non Allroads and I don't know does it have required PWM output for self leveling suspension unit.

In the end I ordered new 4Z7941285C from Audi dealership, 110 GBP and delivery is in 2 work days. Used ones where around 70 GBP (inc. VAT and shipping costs to Croatia) but I didn't want to wait and risk to order used one to end up with other known problem's with that sensor (corrosion, etc.).

I done previously 402 mod without problems thanks to:

https://www.audiworld.com/forums/aud...t-how-2038902/

BR, Jura.

jgospodaric

Changed the sensor, and yep it was due sensor fault - now with new one works ok. Again tried to heat up and reinstall old faulty one but no success. Checked resistor they seams ok, IC is ASIC type so I stopped there.

Checked height and there was no need for 402 mod every wheel was in the same position on all levels.

Will try to investigate further if 4B0907503A can be used as replacement - I doubt but let we see

BR, Jura.