Land Rover Repair: Disco II EAS - left rear drops when off but OK when running, orings, valve body

Question
Hi Dennis:  2003 Disco II; left-rear tire drops intermittently when vehicle is
off
but raises and operates ok when running.  Sounds to me like if the
suspension tries to adjust after being shut off, the valve to lower that side
opens  (air sounds like it is escaping) but does not "click" closed again.  Other
times it it levels and clicks off with no trouble.  I'm guessing it is not a
problem when running because the movement of the car giggles the valve
closed and it is just sticking a bit?  Is this the solenoid sticking or the valve
body itself? Is it easily self-serviceable?  My local shop wants me to ditch the
whole system for regular shocks to the tune of $1800!  Thanks so much in
advance for your advice.  -Chris

Answer
If the valve is binding up it should be possible to clean and re-seal with new orings.  If the ECU is holding it open there may be something wrong with the height sensor, giving a false  reading higher than what it should be.  I don't have much experience with the DII system, but ditching should be your last option, and $1800 is way too much.  It's less than $300 in hardware.