Has anyone here done anything with the suspension calibration via SDD on the X351.

I reset my suspension having replaced a height sensor but I cannot get it calibrated - the car raises the suspension, then lowers it to normal and seeks the measurements, then it bitches that the rear measurements are wrong and outside tolerance - well of course they are but the car put it at the height, the car is the thing setting the height and then bitching - there doesn't seem to be a way to clear any previous calculated offsets so I can't get past this step in calibration - of course it is out of spec that is why I want to calibrate FFS .... would be so much easier if you code raise or lower a corner independently to get it to spec then store the values.

Anyone had this particular challenge ?

 

This are from X351 Service and Repair manual available from sticky section from this forum:

By your explanation your vehicle are working exaclty correct right now, after you changed one front sensor. Vehicle see 3 other sensor giving sensible values and using these values to set it on level by using "triangle" quess by rear wheels. New sensor are giving out of range value, and vehicle complains that, like it should do. Note: x351 have height control only on rear, your vehicle try to compensate wrong value from front corner by rear wheels, after it have tested that the rear sensors giving sensible values for the increased/decreased suspension movements. If you sit and think a moment you will find this make sense.
You should start Suspension calibration process from SDD. If i remenber right the process will ask you measurements of each wheel. There are on mechanical tool available for the measurement, but as far as i remember the measurement SDD are asking are distance from wheel arc edge to the center of the wheel. This can be measured with std tapemeter. Once you give the distance, the system stores it with the value received from sensor. After you have given all distances the system are able to level the vehicle. (somehow i have an slight memory that it will ask to recheck the values again after levelling, but i might mix this memory with Citroen/PSA or MB prosedure)

 

^ Pretty much. What I did was use the height spec for the fronts as a guide as your corner to corner distances are related, since the rears are the only ones actually leveling, the front springs just adjust mechanically based on what the rears are set at.

Technically there's a mechanical tool you should use to measure center hub to wheel arch, I just used a tape measure. You want to get your fronts in spec and the rears adjust accordingly (in millimeters). In the sticky shop manual on this forum there's a section that calls out acceptable specifications for measurement distance. I made up a few numbers to get mine in spec first, then dialed it in with measurement.

 

No they are not correct and I replaced a rear sensor, I do have the tool, the car is raising the rear left too high so it is 'out of spec' - since it is using old values clearly and refuses to 'learn' because it is out of spec - so it is catch 22 - the rear left is 15mm too high compared to the rear right both fronts are in spec. I have 396 and 397 on front Left and Right respective and 422 vs 405 on the rear left and right respective - so the rear left is out of spec - I know this but the car put it there !! - the rear left sensor had an intermittent fault.

@dmchao when you say you made up a few numbers is that just to get past the entering of the heights - is there a dialog after that where you can set the correct offsets ?

 

Not to my knowledge, I did not think there were digital offsets, only mechanical. Is the sensor installed at the correct location?

 

It is in pretty much the only place it can go, the voltage reported in live data does not match between sides either when the car thinks it is level, in fact the voltage indicates the left is higher which it is in reality but the car is being terminally stupid and is showing -12 for the right hand calibration whatever that means and I can't set that to zero. This procedure is not following a logical calibration path, I guess I'm tearing it all off again - getting really tired of this car and its BS.

 

Sorry: Somehow i got impression that you changed front suspension parts and sensor.
You cant set the measured voltage for zero: You need to tell the system what are the height of this measured voltage, what new sensor are sending. Obiosly old sensor sent different voltage on the same reached sensor arm angle: Thats why you have now dirrerent position for the car. (system dosent have an eyes outside to see -> You are the eyes) Ideally voltage would be nice to convert directly for millimeters, but unfortynally voltages sensors are sending have nothing to do for the height itself. Its just measured value, depending the sensor itself and mechanical tolerances of the arm and mountings.
Read this: (Taken from JLR manual)
Just calm down and think a bit. Then proceed with SDD calibrating process thru.
From my memory by "chancing componet " path. (i did it about 4-5 years ago when i notised my car was not sitting exactly level. Left side was bit higher. Sorry, cant remember the process exactly path on SDD)

 

Yes, in my guidance of "playing around with values" there can be any number of reasons for deviation after calibration. I would venture a guess there is nothing wrong with the module performing the calibration calculations. If you want your left to go higher, set it to be lower than nominal. If you want right to be higher, set it to be lower than nominal. I did this one time, then dialed it in with 3 measurements at each wheel as the manual intended. I did not have that nice center hub tool though.

 

That is the issue - the ONLY reason the car is too high at the rear left is because the car is putting it there, it refuses to do any adjustment as the height is 'out of spec' which is the whole point of trying to calibrate in the first place, it is infuriating, so perhaps I need to fake the measurements but keep within tolerance and see what I can do to get it to behave.

 

Yes, that is what I'm implying. You must find a suitable value close enough to nominal. Then it will adjust, then you can run probably the same calibration sequence again to bring it in closer. If that doesn't work, I really don't know what else could be done by end users.

Let's say your wheel arch and wheel gap is like 50mm (impossible but for sake of discussion). Calibrate it to something like 4-5mm outside of nominal tolerance and the sequence should begin. At that point I'd keep dialing it in. I had a similar situation, probably not the same huge gap in one side vs the other that you may have, but the out of tolerance road block gave me some grief at first.

 

Did someone used Icarsoft lr v3 for suspension calibration on x351?