Citroen XM Forum

Hi Russ

A H2B or a H2 hydractive ECU are plug and function compatible with your H3 ECU.
Just though I would mention that as just in case it makes easier to borrow one to try.

John

That would be good John. Now the cheeky question, would you have one for me to try?

Ciaran wrote:

The standard behaviour of the suspension is that when any of the door or tailgate switches are triggered, that the computer will close the centre spheres, putting the car in hard mode. The idea here is that it will prevent any sudden body movements or alterations in height (that are more prolific in soft mode) from happening while passengers may be getting in or out of the car.

Other way round Ciaran, the doors make the system engage soft mode.

It sounds like Russ's car is engaging hard mode too readily and went into soft mode when he opened the door. It should have been in soft mode below 18mph anyway.

Apologies, you're quite right Will.

I always thought it was the other way round to prevent movement and roll.

Either way it does at least prove that Russ' valves are being engaged by the computer at some point, even if somethings triggering it to hard mode too readily when driving, but at least it shows that the ECU isn't completely DOA if it's able to do that...

Sorry for the misleading statement Russ.

Ciarán

Matthew (MTXM) had the same problem, he disconnected the speed sensor as a get by.

I can't remember what the fix was.

All very interesting. I'll have to ask Matthew what he did. Don't worry Ciaran it is complicated, mind you your description made perfect sense too!!

I have just been wrestling with the fuesboard to replace the front windows relay. Exhausted now!!! a successful swap. they work again.

But I found fuse 19 the Hydractive ECU fuse to be blown.
So obviously the next step is to replace it and see what happens.

Blown fuse will do it alright, I found at least 3 seem to be related to the Hydractive at some juncture, and often the fuse listings in the manuals can be inaccurate.

I discovered one by accident once because my alarm and deadlocks stopped working, replaced that fuse and suddenly found the orange suspension light came back to life and the inexplcibly hard ride from that morning was suddenly cured

It's strange how they are all linked what effects what ect. I know one thing, that orange light won't light up when I replace that fuse!!

Ciaran, soft mode with doors open has one major reason: if it stayed in hard mode, the centre sphere would remain isolated. Any pressure difference would then cause a sudden jolt when the car starts and the computer first switches to soft. Basically, soft here means open to any pressure changes.

Sent from my Nexus 7 using Tapatalk

That explains it, thanks Gábor