P38A Strange rear air suspension fault

Hi all, have looked across the forum, if I have missed it sorry please point me at it;
P38 MY 2000
· When on maximum high air no problems and will sit on high air for weeks and not drop at all.
· When on maximum low air no problems stays down and pops back up within a very few seconds of pressing the button.
· When on normal height, as soon as I park the rear, only the rear drops to maximum low, front stays as is. When being driven only the rear drops to max low slowly you can’t tell but you feel her pop back up very quickly.
· Motorway height, if the lock button is pressed to hold her there, as soon as I park the rear, only the rear drops to maximum low. When being driven without the lock button pressed the rear drops to max low slowly you can’t tell but you feel her pop back up very quickly.
· In normal or motorway height when driven with the lock button pressed it seems to stay at that height, which is to say I have not noticed it change height.

Now I think I can rule out the bags, otherwise it would not sit at max height for weeks when left alone, would it?
There are no lights or warnings on the dash.
Am I looking at height sensors or valves somewhere?
The only thing I know for sure its steadily getting worse – i.e. happening more frequently when being driven.
Any pointers please?
Many thanks

If you haven't got a Nanocom or EAS lead I suggest you contact Datatek and get a diagnostic lead off him. Then you can see what the car thinks is happening.
When you say it will stay for weeks, is that without using the car at all? EAS delay relay removed?

For clarity, if I don't need the car and that can be for a few weeks at a time, I put her on full air (always have was advised years ago to do so – can’t remember why now) and disconnect the battery (saves flat battery). If the bags were leaking she would drop down over time I assume?

More than likely, depends where the hole is and how the bags fold so not impossible.

Think you need Datatek's lead with the Storey Wilson software. See what the target heights and actuals are.

I'd guess at perished air bags. I have a Subaru Legacy with air suspension and the front bags perished at the point where the bag 'folds' in normal height, causing it to drop when parked. If I raised the suspension before parking it, it was fine because as the bags inflated the point where the fold was normally was 'unfolded' forcing the perished bits of the airbag to seal up. If that makes any sense!!

killerhaggis said:

Hi All,
Left over night on Normal height it is on bump stops in morning, On High Height left over night it stays at high height, done this several times to check, all height settings are achieved in seconds both up and down, Eas pump does seem to run a bit more than i would have expected, I cant find any obvious air leaks. Will plug EAS software in at weekend though, any suggestions? why would it stay up on high height but not on normal?

Thanks Del

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Datatek said:

Leaking airbags if the are old, the leaks open and close where they fold under, so may seal on high.
Bags have a design life of 7/8 years 80K miles.

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Grrrrrr said:

Pull the EAS relay from under the passenger seat. should show which corner is dropping.

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Datatek said:

Leave it at normal height when you do it.

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Turned out to be n/s rear bag leaking, replaced both rears and will replace fronts after Hols

7/8 years and 80K life design, think its time for new bags they are 15 years old and 120K
Will do the EAS relay test at the weekend to prove the bag(s)
Thanks guys