js671gb
Member Since: 22 Feb 2018
Location: Cotswolds
Posts: 26
  
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| Suspension - Multiple faults? |
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Afternoon team!
D3 has been worked hard recently and has developed into quite a vocal beast with its 'bongs' & suspension faults. 55 plate.
I've had it drop to the bump stops & then raise itself at 80 on the A1 & I've also had it get stuck in off road & refuse to drop with a C1A1364 code as soon as you hit the down button. You *can* eventually get it to drop after a few reboots.
The left rear height sensor also looks like the wheel has dropped through the floor on the 4x4 info display. When it does so SDD is telling me that its reading 0 volts. It then comes back to normal soon after.
My plan, and what I wanted to run by the brain trust is:-
* Replace the NSR height sensor (LR020159?) - it appears to have 3 wires going into it so I guess its been replaced
* Recal the suspension with SDD & a tape measure
* Refresh the silica etc in the air dryer
On the last point - I've tried the trick to take the air dryer screw out without taking the compressor out and it is *impossible* - I snapped part of the plastic collar in the process (don't ask...) - any other tips before I bite the bullet & drop the whole compressor?
Can I drop the compressor from its mounts, remove the front air pipes that go into the dryer & the power etc connectors, and just tip it down, supported, with the intake/exhaust pipes still attached, or am I going to have to deal with those seized olives in the rear? I'm kind of hoping I can just let it "dangle" (supported) & get the screw out that way?
My planned process for changing the height sensor is to crack the wheel nuts, get the truck up on a jack & stands on that side only, pop the wheel off, get the 2 torxs off, and replace the sensor - anything I"m missing, it seems too simple?!
Seems to have all come at once - I've done the wash bottle, oil change & had 3 windscreens in the last 4 months haha
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 6th Sep 2020 3:48 pm |
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Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10635
 
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I think I would remove the 20A fuse from under the bonnet before changing the sensor for safety.
It could be a wiring issue though.
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| 6th Sep 2020 4:03 pm |
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js671gb
Member Since: 22 Feb 2018
Location: Cotswolds
Posts: 26
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Well caught Pete - see, this is why I asked haha
I’d considered wiring, but had ruled it out on the grounds that the wheel drop part of the problem only happens when the truck is at normal height - to my mind that suggests a worn track on the height sensor which again, to my mind (as a broadcast engineer haha) is typical behaviour of a “bad pot”
The wiring is up under the NSF arch isn’t it?
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| 6th Sep 2020 4:53 pm |
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js671gb
Member Since: 22 Feb 2018
Location: Cotswolds
Posts: 26
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For reference, sensor values:
Front Right -16mm 2.08v
Front Left -6mm 2.13v
Back Left 11mm 0.00v (then goes to 45mm 2.42v when you rock the truck around, and doesnt drop when in off road!)
Back Right 52mm 2.17v
Pressure sense: 213kPa 0.62v
Comp temp: 69c
All valves closed
Either way the cal is very obviously a bit out although the drive slopes towards the back a bit 
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| 6th Sep 2020 5:03 pm |
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Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10635
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You may well have a valid point. It could be a bad pot if it happens at one height.
Wiring failure to these aren’t unknown though.
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| 6th Sep 2020 6:11 pm |
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js671gb
Member Since: 22 Feb 2018
Location: Cotswolds
Posts: 26
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New sensor has been ordered & will give it a crack this week, so we’ll find out I guess
From the research on here it seems to be the wiring behind the wheel arch that is prone to giving up, which is easy enough to whip out (had the lower front half out to do the wash bottle some time ago)
I’ve also ordered some new clips for the compressor so I can try dropping that to do the air dryer.
The truck has done 6000 miles in just under 2 months so I think I’ve done quite well to only have 2 faults hahaha
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| 7th Sep 2020 4:36 am |
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lampie73
Member Since: 29 Jul 2020
Location: Leicstershire
Posts: 20
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If you have the Hitachi compressor you don't need to remove it. You can get the Airdryer off in situ. I've done this a few weeks back and it was an easy job.. apart from the screw on the top
https://www.disco3.co.uk/forum/dryer-assembly-removal-177424.html
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| 7th Sep 2020 11:08 am |
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js671gb
Member Since: 22 Feb 2018
Location: Cotswolds
Posts: 26
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lampie73 wrote:If you have the Hitachi compressor you don't need to remove it. You can get the Airdryer off in situ. I've done this a few weeks back and it was an easy job.. apart from the screw on the top
That screw is the bain of my life - I wasted 3 hours on Sunday afternoon trying to get something to go into it - no dice.
The key being you had an old spanner you could bend up & I haven't  I only have the good socket/spanner set - and nothing else I've tried will work 
Can we find whoever came up with the idea of a screw you can only get out from somewhere you can't access & have a public whipping?!
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| 7th Sep 2020 7:04 pm |
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lampie73
Member Since: 29 Jul 2020
Location: Leicstershire
Posts: 20
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I managed to do it with a philips bit and a ring spanner. I had to hold the bit down with one finger and use the spanner at an awkward angle...
But I agree a public whipping is in order...
Edit: Also I ripped out all the bloody foam nonsense, so access was a bit easier. Compressor is a bit noisier, but that doesn't bother me...
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| 7th Sep 2020 7:13 pm |
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js671gb
Member Since: 22 Feb 2018
Location: Cotswolds
Posts: 26
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The bloody foam nonsense is what stopped me getting a few UJs in on a ratchet - just hard enough not to budge.
Good news, I’m under it now - wiring behind the arches is fine, pics to follow. And the compressor has been off before - whoever did it left the top bolt off? And the 2 bottom bolts turned first try after some WD. And, bonus....the olives at the back of the compressor were WDd & after coffee they move too.
So, I take from this it’s had a new compressor before it came to me - or it has at the very least been off!
As soon as my kit of bits comes I’ll whip it off & do it.
Did I read there is a grey rear connector block to check too? Can’t find it for the bloody life of me! Any clues?
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| 8th Sep 2020 8:44 am |
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js671gb
Member Since: 22 Feb 2018
Location: Cotswolds
Posts: 26
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Well
I found the rear connector block & it’s fine!
I’m trying to find the silencer in the rear cubby but mine is full of rear AC gubbins!!
Errr?!
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| 8th Sep 2020 1:10 pm |
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js671gb
Member Since: 22 Feb 2018
Location: Cotswolds
Posts: 26
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Partial success
A reminder of the symptoms
Dodgy left rear height sensor (have the sensor but still not changed as haven't totally resolved pressure problem yet & the sensor arrived sans screws)
"Pressure does not decrease while venting gallery"
**************
I whipped the compressor off today and took the air dryer off - well, it was totally stuffed. Filters hard, dessicant full of powder. Just as I'd expected. The O-ring on the compressor where the air dryer meets had turned to stone too. The refurb took about 15 minutes tops, and all closed back up fine. I made sure to inspect the dryer cap for cracks, and it looked good.
Refitted - cleared DTCs in SDD and boom, no more "Pressure does not decrease" code.
Nope, instead I got the opposite hahaha "Pressure increases too slow when filling reservoir"
My silly brain says that if this code was going to trip it would've done with the blocked dryer & that now with a new dryer (essentially) it shouldn't be there if it wasn't beforehand. Even when the compressor was whining about pressure not decreasing it wouldn't whine about it not increasing.
Prior to the change it was making 1763 kPa
After the change its now making 1200 (ish) kPa
Exhaust valve working fine.
My next go-to idea is that I've perhaps not pushed the blue pipe in properly on the dryer, or the cap has cracked invisibly, or the O ring in either end has been pinched when refitted. So out with some soapy water. Would everyone concur?
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| 9th Sep 2020 2:17 pm |
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lampie73
Member Since: 29 Jul 2020
Location: Leicstershire
Posts: 20
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I guess soapy water is the way to go... If got the old cap flying about somewhere if you need a new one.
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| 9th Sep 2020 2:31 pm |
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js671gb
Member Since: 22 Feb 2018
Location: Cotswolds
Posts: 26
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I'll get out there with my squeaky clean sopy water later & have a spray & pray  the more likely explantion is that I've managed to stuff something up, or not pushed hard enough
Thanks for the offer on the old cap - I may well be taking you up on that if thats the issue 
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| 9th Sep 2020 3:00 pm |
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greg00
Member Since: 08 Dec 2017
Location: Zurich
Posts: 162
 
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I‘m also dealing with "Pressure does not decrease while venting gallery".
Used a lot of soapy water but couldn‘t find any leak.
I replaced Hitachi with AMK 3 months ago.
IID live data shows that exhaust valve is working and it vents when gallery pressure is high (more than 500kpa). But it vents only down to 390-400kpa. Usuallly after starting engine pressure rises quickly to 400kpa. Then you get the boing of death.
Could it be a defective pressure sensor in reservoir valve block or exhaust valve on AMK not working properly? Or maybe a non visible leak on the air tank on top?
This fault code is hard to figure out - especially with a brand new compressor installed that used to work before.  _,,,_______///________
/// LR3 SE V8 Java Black
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| 10th Sep 2020 10:25 pm |
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