After fitting a new front air spring I checked the heights of all four wheels on level 2 once it had settled down using a tape measure as a quick guide. Measuring from the centre of the hub to wheel arch above I got 410mm and 427mm at the front and 396 and 420 at the rear.

I did a 402 check useing Ross-Tec VCDS and found that 402 was still shown as the default. Pity cus I had hoped to find that these may have been corrupted or messed with by previous owners.

I know work has been done on replacing worn sespention bits before and Audi recommend that level sensors should be adjusted once suspension parts have been replaced or disconnected.

Anyone know anything about this and how to do it?

Any help or ideas would be much appreciated.

 

Did you preform height level calibration so called 402 mod?

https://www.audiworld.com/forums/sho...2038902&page=6

Even though the actual 4 corners height is crazy, the vcds system always recognize as the height should be 402mm.
You need to input the actual measured value to each channel to perform the height calibration.

 

Already followed the method in the link you sent and as I said in my thread I re-entered 402 for each corner and saved the setting.

Are you saying I should have entered different numbers for each wheel depending how far they are out of height? I thought 402 is 'normal' for level 2 so if the wheels are crazy then the error is somewhere else.

What about the physics adjustment of the sensors, dont they need moving to get each wheel the same height?

 

Yes, i am.
You should enter the different value for each corner to crrect the height diffference.
i think you should enter the number 410 and 427, 396, 420 to each channel.
Login code 31564
Channel 1 : FL
Channel 2 : FR
Channel 3 : RL
Channel 4 : RR
Channel 5 : enter "1" to save those numbers

Do you have Bentley repair manual?
Not sure i can post the page of that just considering to copy right.

 

allroad55 is absolutely correct.

 

No...just leave the sensor alone.

The system reads the sensor's position as it adjusts the height of each wheel to a measurement of 402. Note that I did not say 402 "millimeters".

When you go through the "adaption" (a.k.a. calibration) procedure, what you are really doing is telling the system the "number of units" each height sensor is currently reading. There is no measurement ruler within the sensors which reads in millimeters. The sensors simply determine a relative change in position.

The sensors were designed to resolve changes in incremental units. Each of these incremental units is approximately one millimeter. This is why Audi uses millimeters as the unit of measurement. To repeat...there is no millimeter scale anywhere...just an ability to sense changes in incremental units which approximate one millimeter.

When you save to Channel 5 the value "1", you are telling the system to re-adjust the height of each wheel to 402. It can do this because you had just told the controller the actual height of each corner. Since the sensors are designed to resolve changes in incremental steps, the system will move each corner (up or down) the number of steps it differs from 402. As mentioned, each step is approximately one millimeter. If you had said a corner was at 410, the system will move that corner down 8 incremental units (millimeters) on the sensor.

I hope this helps somewhat in understanding how the system works.

 

Many thanks Allroad55 and Mr.Timewise for your detailed replies, now you've explained a bit about how the thing works then I can see what I need to do.

As you might have guessed I'm fairly new to Allroad maintainance (worked on many other vehicles) and was dreading the day that I'd have to have a bash at Air suspension but with the generous help from members of this forum I'm gaining a bit of confidence. To be very honest, I just could not afford the cost of getting an Audi dealership to do these jobs for me.

 

I calculated backwards here. See my next post below.

 

MikeB, are you sure???? According to your own post in the original 402 MOD thread by Nebuchadnezzar...

https://www.audiworld.com/forums/sho...0&postcount=46

...the correction method is to use the actual measurement (or , as you said, just add the height error to 402) when programming each channel. That is, if the corner is high by 8 mm (i.e., 410) then enter 410 (402+8=410) into the "new value" field.

The specific example from the original 402 mod post by Nebuchadnezzar states:

"...to lower the allroad 15mm, we would tell the computer that the allroad measured "417" and enter that into the New Value field. To raise the allroad 15mm, we would enter in "387"..."

I used this method to adjust my four corners several times with perfect success as I played around and after I installed new air springs and shocks.

 

The following calculations should be correct. Don't hesitate to correct me if I'm wrong again.
You are trying to correct incorrect levels, so you have to do the math:
Enter 418 for channel 1,
Calculation: 410-402=8; 410+8=418.
Enter 452 for channel 2,
Calculation: 427-402=25; 427+25=452.
Enter 390 for channel 3,
Calculation: 402-396=6; 396-6=390.
Enter 438 for channel 4,
Calculation: 420-402=18; 420+18=438.
You are trying to <b><i>correct the measured levels</i></B> back to 402.
Once you get them corrected the car should be level, assuming that all of those very difficult measurements were correct.
Good luck