Xenons "home position" either dips or goes high after a few days usage

[Juka]

Hi all, I have a weird problem - my xenon's home position goes haywire after a few days of usage. I did VCDS homing, and setting correct level multiple times, works ok for a few days then either very high or very low home/zero position.

 

Notes :

- In VCDS I do have an "internal memory error" on the xenon modules I cannot reset, but this is there for years now.

- Leveling itself works perfect, if I burdain the car it always goes to home position, so the motors and level sensors work obviously (?).

- Rear level sensor works perfect, if I sit in the trunk, the level is automatically adjusted within a second.

- I didn't have this problem until I overhauled whole suspension front/rear - front/rear level sensors had to be dismantled and put back again, maybe they are physically not at zero? How to check them for correct level?

 

Thanks for any inputs.

 

Octavia 2002 1.8T Combi Elegance.

[nige8021]

Specified values of the sender Voltage on the front sender when the vehicle is stationary without load: 2.3 - 2.8 V. Voltage on the rear sender when the vehicle is stationary without load for front-wheel drive: 1.9 - 2.3 V.   You should find these voltages in the measuring blocks for the headlight modules 29/39

[Juka]

Thanks @nige8021I did check them via VCDS just now and indeed, the rear sensor feeds back a healthy ~2.2V and drops nicely as I raise the car (via jack of course).

 

On the other hand, the front sensor seems busted, it's stuck at ~1.05V and doesn't budge at all even raising the car. I've undone the bracket and only in the topmost position it drops a bit to ~0.9V, if I overdo it and let the arms scrub against the housing and wiring it drops to ~0.4V. But in the actual working area the voltage is stuck.

 

Well there I have it, I guess a faulty front level sensor, anyone has a part number on hand to save me some time searching?

 

Anyone had similar faults is it a common issue on O1's?

 

 

[nige8021]

https://skoda.7zap.com/en/cz/octavia/oct/2001-252/9/941-941025/ 

[Juka]

Thanks again @nige8021 

 

Well, since the front sensor is worth 10% of the car itself, I went down the faithful "VW failsafe logic", hoping that the system will work if there is no sensor, that is if I just unplug it, which I did (with quite some effort).

 

Lo and behold - immediately as I turned the key, the zero/home position is back to where it should be. Checking the faults, there is a new fault "front sensor signal too low" which means I did a perfect job.

 

However - the failsafe seems to work in a manner the auto-leveling during driving no longer works, level is fixed, tried jumping in the trunk as before, the beam just goes up or down. I'm good with this until I source a new sensor ("hi mum, can you drive over with your O1 1.8T w/xenons, I have something to check out..." :))