I have the "Suspension Fault Normal Height Only" on the dash.
The error codes are C1A09-1C Pressure Sensor Signal - circuit voltage out of range.
The gallery pressure is reading 0.19 bar.
I can clear the fault and press the raise button and the car will rise. The gallery pressure can get up to 15 bar. I have removed the sintered filter to see if that makes any difference but it doesn't.
When I drop the car down to normal level the fault reappears.
We have had a split front RH air bag and I replaced this yesterday. Seemed to be fine after fitting this but about 20 miles later this fault appeared.
Its an AMK compressor. The compressor does seem to be on a long time.
When I disconnect the pressure sensor on the compressor I would expect the pressure reading to go into error but it stays at 0.19 bar. The pressure sensor voltage does go to zero when I disconnect it.
Any ideas?
I was thinking about servicing the compressor to see if that helps. Maybe a level sensor?

The car is a 2008 L322 Vogue TDV8.

Click image to enlarge

Click image to enlarge

Click image to enlarge

Update. I drained the reservoir and bags with the GAPIID tool. The car was then on its bump stops.
Started the car and then was monitoring the compressor and it struggled to build 6 bar. It suddenly lost pressure before building back up and eventually the temp limit on the compressor kicked it shutting it down. However the car did rise off the bump stops. So now suspecting it could be the compressor worn out.

At one time you could get a service kit with all the seals etc. not sure if you still can.

 2011 Range Rover Vogue SE 4.4 TDV8

Previous cars :
2003 Range Rover Vogue TD6
1999 Discovery Td5 ES
1995 BMW M5 3.8 6 speed
1992 Range Rover 3.9 Efi Vogue
1992 BMW M5 3.8
1988 BMW 735i SE
1989 Ford Sierra XR4x4 2.9i
1981 Ford Fiesta Supersport

Hopefully this fault is now fixed (for a while anyway). I bought a AMK Filtration and Exhaust Solenoid kit from 4x4Airseals to service the compressor. Its easy to do and just followed the 4x4Airseals videos on youtube. The fault does not reoccur on the GAPIID tool even after a test drive. When the system has vented there is now 1.35bar in the gallery compared to 0.19bar previously, so something has changed. The pressure builds to 15.5 bar in the gallery before cutting out the compressor. Previously the fault occured straight away. 4x4Airseals were rally good and delivery was rapid. Definately recommend them.