Xm mk2 HA2 fault finding

nino1 · Post by **nino1** » 28 Feb 2006, 10:26

Hi, any easy reliable way to find out if the hydractive spheres
are up to the job on a HA2 xm?

Tnx.

Mandrake · Post by **Mandrake** » 28 Feb 2006, 10:32

Perhaps you could describe the symptoms you're trying to solve first.

Yes, there are ways....

A simple initial test is to idle the engine and do a bounce test and the front and rear and note how soft it is, then remove the fuse powering the hydractive computer and do a bounce test again - with the power on it should be rather soft, with it removed it should be quite stiff with very slow rebound damping.

If it's stiff with slow damping in both power on and off states, that end of the car probably has a flat hydractive centre sphere. (But it can be a fault elsewhere too like an electrovalve, in unlikely cases)

If it is completely rigid in the off state, the outer strut spheres could be flat, although the damping is so heavy at the front in the hard mode that its difficult to distinguish flat front strut spheres just from a bounce test....

Regards,
Simon

nino1 · Post by **nino1** » 28 Feb 2006, 10:53

It's just feeling that maybe the differance between the sport
and automatic mode isn't making sufficient difference.
Could i do a bounce test by switching the auto/sport?

IMHO the sport mode on the HA2 is active in a way?

AndersDK · Post by **AndersDK** » 28 Feb 2006, 14:18

You can not select a more sporty (firm) suspension by switching from auto to sport. Thats not how the HA2 is doing the job.

When you set the switch to sport - the HA2 computer uses a different set of parameters for its decison to switch from soft to hard mode. And it only does so while driving.

When the car is stationary and engine idling, the suspension is always in soft mode, no matter how you set the switch.
When engine is stopped and a set time has elapsed, the suspension system switches to hard mode and stays so until engine is started again.

In other words, to test the spheres in the 2 modes :

1) testing the hard mode. This is the mode where the middle (extra axle sphere) is NOT connected. Only the wheel cylinder spheres are active - just like any other hydropneumatic Citroen. Engine stopped, ignition off, wait 2 minutes for the system timer to elapse.

2) testing the soft mode. This is the mode where the extra axle sphere is connected to the suspension hydraulics circuit. In effect this equals a swap to larger volume spheres fitted to each axles suspension.
Engine must be running idle.

nino1 · Post by **nino1** » 28 Feb 2006, 14:57

Doesn't anti-sink affect the "hard" test

Post by **RichardW** » 28 Feb 2006, 15:12

"Doesn't anti-sink affect the "hard" test"

It shouldn't, but might if one of the hydractive valves is leaking, and has dumped all the system pressure (mine does this!).

By the way, don't try test 1 with a door open - as this puts it in soft mode

You should be able to hear the electrovalves whining/humming with a door open and the engine off.

nino1 · Post by **nino1** » 28 Feb 2006, 18:24

I did the test.
It behaved like you said.
Hard after being turned off, soft with the ignition on.

I suspect the front spheres are no at their best, so this
is where the problem most likely lies.

tnx.