Hi

If you have a diagnostic tool that supports live values, you should be able to watch the gallery pressure drop (exhaust valve opening) just before the air compressor starts. You can force the air compressor to start by calling for a height change. The exhaust valve vents the gallery pressure to allow the air compressor to start up more easily.

U can get rebuild kits , managed to find a link for u, that’s if it’s an AMK and not a hitachi or Dunlop, but of course need to ensure voltage is getting to the exhaust valve before changing anything

Need to also ensure the dryer silica hasn’t blocked up the internal filters or material


Ref C1A70, plse check the wires and connector pins at that height sensor to ensure there’s no breaks or dirty contacts

Hopefully the code reader via live data would give u the supply voltage

Hope that helps u

Meant to add if u want wiring diagrams etc plse let me and will find some for u , as then ur be able to see what colour wires do what on each height sensor , compressor etc

Out of curiosity where abouts are u plse as never know someone might be near u if u get really stuck