Hydractive Summary

Although every aspect of the functioning of the Hydractive systems was described in the previous chapters, considering the number or factors influencing the suspension and the amount of rules and decisions made by the computer, it is not easy to grasp the actual behavior of the car, including the differences in the various Hydractive generations. To make it easier, we summarize how the various Hydractive systems work in real life.

Hydractive 1

This suspension system was used on early XMs. When you open the doors or the tailgate, the car will switch to soft mode. As you get into the car or put luggage into it, it stays soft for as long as any of the doors are open (but for a maximum of ten minutes, with the exception of very early XMs without this extra timer). When you shut the doors and switch the ignition on, the car will remain in (or switch to) soft mode.

As you drive off, the car will still stay in soft mode for 30 seconds or until you reach a speed of 30 km/h, whichever comes first. After that time or above that speed, the car will behave normally, depending on the setting of the dashboard switch.

In Comfort setting, it will usually stay in soft and switch to hard mode only if the driving circumstances (rapid acceleration, braking, fast cornering) call for it. In Sport mode, it will be in hard mode constantly.

As you stop the car, switch the ignition off or open any of the doors (actually, even if you open the door with the car still rolling below 30 km/h; but if you are foolish enough to open the doors above that speed, the suspension will not be interested in it), the system will switch to soft mode and behave just like it did before driving off: soft as long as the doors are open plus 30 seconds, but no more than ten minutes.

Hydractive 2

This version was used on later XMs and Xantiae. Its operation is in many ways similar to the first version, but with some differences:

When you open the doors or the tailgate, the car will switch to soft mode. As you get into the car or put luggage into it, it stays soft for as long as any of the doors are open (but for a maximum of ten minutes). When you shut the doors and switch the ignition on, ther car will remain in (or switch to) soft mode.

As you drive off, the car will still stay in soft mode for 30 seconds or until you reach a speed of 24 km/h, whichever comes first. After that time or above that speed, the car will behave normally, depending on the setting of the dashboard switch.

In both the Normal and the Sport setting, the car will usually stay in soft and switch to hard mode only if the driving circumstances (rapid acceleration, braking, fast cornering) call for it, however, it will do so more often and in response to smaller, less dynamic driving maneuvers.

As you stop the car, switch the ignition off or open any of the doors (actually, even if you open the door with the car still rolling below 24 km/h; again, opening the doors above that speed will not influence the suspension), the system will switch to soft mode and behave just like it did before driving off: soft as long as the doors are open plus 30 seconds, but never more than ten minutes.

Hydractive 3

This suspension is characteristic of the smaller (1.8 gasoline, 2.0 diesel) C5’s. It is not really Hydractive in the earlier sense of the word, it does not switch between soft and hard suspension modes, it is more like the simpler hydropneumatic suspension of the CX, GS, BX and some lower spec XMs and Xantiae, with two notable differences:

First, the high pressure suspension fluid pump became electric, making it independent from the engine. Thus, the system will start building up pressure as soon as you unlock the doors using the central locking, without needing to wait for the engine to be started.

Second, the computer supervises the car body height selection, not allowing it to be changed to high or low if the speed is above 10 km/h, or to track above 40 km/h—or, if the height has already been set when the car surpasses these limits, it will modify the body height to be within the range acceptable for the speed.

It will also modify the height of the car body according to the vehicle speed automatically. Above 110 km/h, it will be lowered by around 15 mm, and the original height resumes when the speed drops below 90 km/h. On poorly surfaced roads, while travelling below 90 km/h, the height will be increased by a maximum of 20 mm.

Hydractive 3+

This is the real third generation of the Hydractive system, to be found on better equipped C5’s (2.0 and 3.0 gasoline, 2.2 diesel). In spite of the technical differences of the system, its apparent behavior is rather similar to the previous one.