Why Does The Car Change Its Height When You Unlock?

[skaramanga]

The Hydractive 3 suspension has always intrigued me with the things it does, like adjusting its height when you unlock the car etc. Also how does it move up even when the car is off? I used to think the engine had to be running for that :)

[techbod]

your is electronically controlled so activated when the key is turned on where the standard none hydro is mechanical and driven by the engine,

 

the height is computer controlled so you don't drive off when its all the way down and wrecking the underside of your car ;)

[Johndouglas]

Also how does it move up even when the car is off?

 

Previous hydraulic Citroens had a pump driven by the engine so before the suspension would rise the engine needed to be running. Hydraulic pumps on the C5 are electronic so the car finds its correct level as soon as the doors are unlocked. You may have noticed that even if you've altered the suspension height, if you drive away the selected height is cancelled and the car assumes its correct height.

[mlkey]

The Hydractive 3 suspension has always intrigued me with the things it does, like adjusting its height when you unlock the car etc. Also how does it move up even when the car is off? I used to think the engine had to be running for that :D

 

As mentioned, being electronic, can be adjusted without engine. As for when you unlock the car, this is due to the temperature changes causing the pressure to increase or reduce, therefore changing the cars height while parked. This is easily proven as you lock the car in the evening and come back to it on a cold morning, you will see it raise itself to compensate for the drop in pressure. Likewise, leave it on a cool morning, and return on a hot afternoon, it will drop to compensate for the pressure increase.

 

Hope that helps.