Member Since: 12 Dec 2016
Location: Maidenhead
Posts: 132
Front cross-link value / drunk suspension
Hi All,
I’ve been hunting after an answer to this for weeks and have read I think all articles associated with valves! But still can’t find an answer to my issue.
For a few months now the old girl has started to drop on one side (drivers). She sinks about 30mm over night and then continues to drop another 10mm each night until the drivers side is almost on bump stops. The passenger side is unaffected and if anything ends up higher, but I’m working on the basis this is just the weight of the car lifting that side in a rotational fashion.
I’ve re-calibrated the suspension with the IID a couple of times but it still happens and no fault codes associated with height sensors but tried it anyway.
The issue mainly affects the drivers rear corner although the drivers front does also sink, but the front seems to stop sinking after dropping 30/40mm.
I can’t see any obvious pin holes in the air lines using soapy water, or hear any hissing.
The compressor is working fine and the car goes up and down into off-road/access without issue and no working lights, also no warning lights in the dash. When starting the car in the morning she goes up and levels ok.
The only fault code I get is as below and to do with the front valve cross over- no power. I wonder if this may account for the quite firm ride recently.
My question is..... would or could the crossover valve cause just the drivers side front to drop? Rather than the whole front end. And if so, could the fact the rear is dropping just be due to the self levelling over night.
I have put it in off-road height and pulled fuse 26 to see if there’s any obvious dropping tonight.
I’ve seen a few articles about chaffed wires to the valve which may account for the “no power” but am equally minded to just swap the whole valve for piece of mind...as much as that exists with these darling vehicles!
I’m mainly trying to establish if the crossover valve can affect just one side in the first instance before I go down the wrong avenue. Any other suggestions very welcome!
Many thanks
3rd Apr 2021 4:37 pm
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10363
I don’t think many people will know the answer to that.
Cross over valve is mainly used for off roading, but who knows, if could be used when parked
3rd Apr 2021 6:15 pm
gstuart
Member Since: 21 Oct 2016
Location: kent
Posts: 13635
Hi
Have u had a look at the connector wiring that sits behind ur passenger side wheel arch liner , along with the wiring at the front valve block itself
Also just wondering if the compressors silica has turned to dust and got into the front valve block allowing it not to seal correctly
Will be interesting to see what happens from the F26 fuse removal of just the front drivers side goes down
Weird with both the drivers side front and rear dropping and not the other side , maybe due to a wiring issue and therefore not allowing the suspension ecu to not get the correct signal ??
But at least ur see what happens in the morning of what’s dropped
Also have u looked onto the gap iid live data , is the crossover valve showing 0%
Plse let us know what the findings are ref the F26 fuse removal and can then at least go from there
Have u got wiring diagrams etc, if not happy to find them for u
Hope that helps a little
3rd Apr 2021 6:16 pm
gstuart
Member Since: 21 Oct 2016
Location: kent
Posts: 13635
Pete K wrote:
I don’t think many people will know the answer to that.
Cross over valve is mainly used for off roading, but who knows, if could be used when parked
Hi Pete
Could it be an error with wiring and therefore the suspensions ecu not getting the correct signal back , therefore not knowing accurately what the height sensors are doing
Ie, wiring connectors behind passenger side wheel arch or front valve block wiring
Of course ur extremely more knowledgeable than myself , wonder if the live date from the gap iid may also be useful
3rd Apr 2021 6:22 pm
ajmacfarlane
Member Since: 12 Dec 2016
Location: Maidenhead
Posts: 132
Hi and thanks for the answers.
The live data shows N/A for crossover valve voltage and 0%.
I tried switching it to off road height and then mud/snow etc while watching the live data to see it it triggered a change and there seemed to be no action, however the car raised and changed settings etc fine.
I’ve not checked the wiring in the arch yet mainly because wiring repairs/tracing cables isn’t my greatest strength.
Does the lack of live data indicate anything in particular, or do I need to put it into low range to trigger a reaction?
3rd Apr 2021 6:36 pm
ajmacfarlane
Member Since: 12 Dec 2016
Location: Maidenhead
Posts: 132
Another thought to add if it’s any relevance...
After calibrating the height sensors (in tight tolerance) I checked the live values on IID for the height positions and they were all difference from each other and nothing like what I’d just set them to.
For example I set the rears to 488mm but the live value said something like 100mm.
Again no fault codes for the height sensors though so I don’t know if I’m reading the live data wrong or if this is any help diagnosing the dropping and cross link valve code.
3rd Apr 2021 6:54 pm
gstuart
Member Since: 21 Oct 2016
Location: kent
Posts: 13635
Hi
Ur so welcome , always a team effort
Did u also check it in rock crawl mode whilst checking the live data , as I believe in that setting it’s when the crossover valve is activated , in order for better articulation
In the mean time Plse let us know what the outcome is tomorrow from the removal of F26 as that will at least tell us if there’s any drop/ leak
Then when u refit F26 try the rock crawl mode and see if there any change regarding data
Do u have a multimeter plse as then if req will be able to check for power at the front valve block, along with continuity with the connectors behind the wheel arch liner
Hope that helps
3rd Apr 2021 6:59 pm
gstuart
Member Since: 21 Oct 2016
Location: kent
Posts: 13635
ajmacfarlane wrote:
Another thought to add if it’s any relevance...
After calibrating the height sensors (in tight tolerance) I checked the live values on IID for the height positions and they were all difference from each other and nothing like what I’d just set them to.
For example I set the rears to 488mm but the live value said something like 100mm.
Again no fault codes for the height sensors though so I don’t know if I’m reading the live data wrong or if this is any help diagnosing the dropping and cross link valve code.
Hi
Tight tolerance I believe is just for when u get the 4 x wheel alignment done, of course will stand corrected on that
As ur getting weird readings would also look into checking the rear passenger side connector ,
Have u replaced any height sensors and if so were they aftermarket one
Personally speaking when I first bought my D3 the suspension was in a right state and felt very overwhelmed as didn’t know where to start of what to look for
Got an enormous amount of help and guidance from here so plse don’t think ur alone
If u test it step by step in small chunks will get there in the end , know my mind was all over the place and learnt to test each thing and ensuring that was 100% working before moving on
When u tried to calibrate the suspension what height setting did I have it in plse, ie access, normal or off road height , thks
Front indeed should be 466 and rears 485 mm from bottom of wheel arch to middle of wheel , think the allowed difference between wheels is 10mm , we’re u using the guided iid program
At least tomorrow after being left overnight we we’ll see if there’s any drop , then put fuse F26 back and check crossover valve on rock crawl, gearbox low and see what data u have plse
Apologises I’m waffling as per usual, lol
Plse let us know what the findings are tomorrow
Many thks
Gary
3rd Apr 2021 7:12 pm
ajmacfarlane
Member Since: 12 Dec 2016
Location: Maidenhead
Posts: 132
Hi Garry and All,
So the saga continues this morning.
After leaving it in off-road height over night (checked the heights were right all round to start with) and pulling fuse 26, the drivers side has dropped again.
It’s the same situation as has been happening. The drivers front has dropped by 15mm, with drivers rear dropping about 30mm.
I’ve not replaced and height sensors yet but had a full set of genuine ones here as that was going to be my first thought. But without a fault code for them or any blinking lights on the 4x4 screen, and now with it still happening with the fuse out I feel it’s got to be something letting-by.
It’s had a new front air bag a couple of years ago so I’d like to think it can’t be the bag.
This comes back to the question of the front crossover valve as it’s the only element with a fault code showing. My first thought is that with its age (54 plate) the valve block/s have become blocked and may be letting-by slowly.
Could the front crossover valve somehow affect the rear suspension too? Or could it be that there is an issue with the front valve and coincidentally also an issue with the rear valve, but without showing a fault code yet?
Thanks
4th Apr 2021 8:01 am
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10363
To me there is an electrical fault. Either valve or wiring and if you off road you should fix it.
There could well be another fault causing the drop
4th Apr 2021 9:18 am
gstuart
Member Since: 21 Oct 2016
Location: kent
Posts: 13635
Hi
So here’s my thoughts on it, with the fuse pulled the valve blocks should all be slammed shut , therefore I’m wondering if the dryer silica material has turned to dust and got under the seals on the valve blocks
Both front and rear valve blocks join to the reservoir valve , so wonder as it’s the closest to the dryer if that’s also letting by and have a leak somewhere , common areas are , compressors end dryer cap, air tank , in ur case drivers side
Alas had this with mine and ended up causing havoc with all the valve blocks as they simply wouldn't seal properly , proved it by pulling a vacuum on each valve block and they all let by
U can get valve block repair kits
I ended up having to isolate sections and pressure testing item by item
Would be tempted to first remove the compressor bottom cover to identify what compressor u have , bubble test the dryer cap and all around the reservoir valve , remove the drivers side wheel arch liner to gain access to the valve block , bubble test all around the pipes, then need to check the wiring at that front valve block due to the error code
Also checking the compressors dryer to see what state the silca material is in
Hopefully one of the other members can also see what they think
Edit , pete has beaten me to it , lol
Last edited by gstuart on 4th Apr 2021 9:25 am. Edited 1 time in total
4th Apr 2021 9:18 am
ajmacfarlane
Member Since: 12 Dec 2016
Location: Maidenhead
Posts: 132
Thanks for the background abs your experience.
I’ve seen a good few posts about the valve locks becoming blocked/not sealing properly so am inclined to think that is what’s happening here.
I had a new compressor fitted by LT dealership a few years ago although not sure which version they fitted.
I’m thinking I need to start by replacing front and rear valve blocks (working on the assumption they are blocked) and see where we go after that.
4th Apr 2021 9:25 am
gstuart
Member Since: 21 Oct 2016
Location: kent
Posts: 13635
Hi
Ur so welcome and happy to help if I can
U can carefully remove the solenoids off the top of the front valve block , will at least give u an indication of condition , ie if it’s full of dryer silica material
If it is u can buy new filters and silica for the compressors dryer , also can get new seals for valve blocks
But would of course be advisable to blow out the air lines if the front valve block is full of dust , as don’t want to repair/ replace them and allow them to also get full of dryer material
See what the wiring and inside is like on the front valve block , then Plse let us know and of course can go from there
4th Apr 2021 9:33 am
gstuart
Member Since: 21 Oct 2016
Location: kent
Posts: 13635
Hope this video helps just in case
Ref compressor make, best to physically check, if u unsure , remove the bottom cover, take a pic and post it here and one of us can tell u what make it is
Plus hope u don’t mind me mentioning it , ur battery needs charging as it’s very low
4th Apr 2021 9:36 am
gstuart
Member Since: 21 Oct 2016
Location: kent
Posts: 13635
Also wiring diagrams for u , plus did u plug ur iid in and select rock crawl / low range to see if the cross link valve percentage changed plse
Plus if u have a multimeter , can test the front valve block solenoids ohm readings on all x 3 and see if there the same
Please don’t think I’m trying to teach u how to suck eggs , but plse ensure u use axle stands
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