I'm new to this forum.
I have just bought a 08 Exclusive C4 Picasso (44k) and as this suspension is all new to me.
I noticed on a couple of occasions that it looked low at the back in the morning, more so one one side, however I would get in and it would adjust itself so I thought it was normal. However one evening I went to the supermarket and when I came back to the car it looked really low on both sides as you could not see the tops of the tires. I started the engine and a warning flagged "don't exceed 5 mph". I panicked and didn't know what to do, however I decided to reverse out slowly and the suspension sorted itself out.
I have since done some research and discovered it to be a common fault. I took it back to the garage and they sent it to Citroen dealer to test and it came back with no fault!! they are nor prepared to replace the airbags, my argument is that this could happen again and I could be stranded somewhere.
Could it be something else that is causing it? such as a valve or compressor or something electrical?