Wind Air Suspension Failure

I had similar issues with my 2012 Citroen C5: ride height problems and error messages. Did you hear any hissing before it failed? Have you checked the compressor relay?

I noticed a faint hissing a few weeks ago. I haven't checked the compressor relay yet. Where is that located?

The hissing confirms my suspicion about the valve. Check the relay, but my issue was a defective air spring valve. With your symptoms and mileage, a workshop visit is likely unavoidable. These systems can be temperamental.

It seems the air spring valve is the problem. The repair estimate is 590€, which is preferable to driving a go-kart. Thanks for confirming my fears.