There is auto-leveling, so could be depending on how you were driving immediately before and how much air is in there, sometimes it needs to dump some air to level things out.
I have the same, sometimes it does it when I get home, sometimes it does not, I did have an XC90 with air 2 cars ago, and it would self level if parked on an incline but I don't recall the same noise.

I'll add on that you may also notice the front getting pumped back up after a faster stop too occasionally depending on how you drive. Also given it's dependent on the density of air, temperature also can plan into how often you notice the adjustments that its making.

 

My guess on this is that it depends on what suspension setting you have it set to. Mine always makes the "pssshhhhh" sound when I lock, but then I always have it set to "Firm", so I assume it's releasing pressure so it's not sitting there holding the system at a needlessly high pressure while it's parked. Then as soon as you start things back up it re-pressurizes.

So, I see it as a way to lessen the stress on the components when not in use.

 

That's interesting, my car never loses pressure when I lock or unlock.

 

I like the sound of that. But mine isnt set to firm. It's standard

 

Mine is also on standard and does this too!

 

Mine as well and its a cool sound. Some trucks are doing this as well to release pressure from the system.

 

I have the same problem. Looking for answers also. Not thrilled to have this. I lemoned a Q7 Audi several years ago when it would lose air suspension regularly.

 

It's not a problem and it doesn't need answers though. It's just how air suspension works.

Air suspension is constantly adding and removing pressure from the system to balance the car based on hundreds of factors, including how much weight is in the car (passengers + luggage), the camber of the road, the settings the driver selects and even the lean angle when cornering.

 

Doe anyone else hear a 'clunk' when they switch modes on the suspension?

 

It’s not a problem. It’s what it does.

 

Good to hear, but I wouldn't like to have my hands on top of the tire when it drops.

 

Is it normal for the air suspension to deflate when parked at the high ride height setting? My RS e-tron GT would stay high, which makes sense when you use it to park close to a charger with a curb you need to be over.

 

I just noticed mine doing this too - I was parked on a bit of an incline and with one wheel on a speed bump. It let out several quite powerful-sounding hisses (scared my dog!). I also saw it move from a parked position, into a slightly more level position when I opened the door the next day. I wonder if it parks itself in a lower pressure state, then adds air in to level when occupants get into the car..
It seems to be fine - it's not sagging on any particular corner when parked on level ground. But it is very loud - certainly a lot louder than my Defender - which would let out air pretty slowly and in small increments.

 

Mine does this sometimes too, i normally keep the suspension in 'nimble', my young son was with me one time when it did it and said 'I think your car just farted!'

 

I have the same behavior, but very occasionally. I’m usually driving in Standard mode. I have a P3 Performance.

 

This is how vehicle AIR SUSPENSION WORKS, right? I don’t understand why any owner would be freaked out unless the car was suddenly sitting like an old, blown out Mercedes.

 

It's a very loud, unusual noise, sporadic, and coming from a car that's been plagued with issues.. Based on the lessons from this forum, it was 50:50 on whether this was by design, or if it's leaving the road on a trailer! I think it's perfectly understandable why there's some concern and folks need to double check this is normal.

I do wonder if some vehicles have valves which are noisier/quieter than others. Mine is louder than a double decker bus suspension. Exactly like a slashed tyre. It doesn't sound like a controlled release, it sounds like something's wrong.

My landrover never released air so aggressively - I quite liked the gentle mechanical sound of the LR equalising the pressure. And I've never heard a BMW or Merc air suspension release pressure in this way.

Now I know it's a 'design feature' I'm fine with it.