suspension Q's

[deian]

Hi all,

Right here we go... my car is the mk1 xantia 1.9td VSX with the hydractive 1(?) suspension, anyhow it has the button near the handbrake that supposedly makes the suspension soft/hard which as far as I understand is the difference between H1 and H2 where H2 is automatic with the switch making the soft sphere switch in sooner and holding it longer.

So am I right in understand that when the switch is on, the electrovalves for the centre sphere should buzz (like it did in my previous xantias when the door was opened) when the sphere is not connected to the hydraulic circuit (i.e hard).

I hear no life from them, I can only try to hear it with the engine off (ignition on of course) cos the engine is too noisy to listen out for it when running.

Now IF they are 'supposed' to make a noise, then obviously mine don't work, in which case I need to investigate more, there is only one obvious engine bay ecu in my car and it has the two plugs, it is the hydractive one one, but do these throw up faults too and resort to hard mode? Or could it be that it may not even be getting a power supply? Could it even be the the diode issue?

Will disconnecting the battery reset the ECU to see if it goes soft, or do I need to actually clear the memory by means of a LEXIA unit or the likes?

What pin is the ECU getting it's voltage from and is it earthed to the chassis (the is an earth nearby).

I'm game on opening up the ECU if need be, but not until I get the basics looked at first, any ideas?

Thanks

p.s I gave up on the sordid fuel sender twist on cap. How annoying! No biggie though.

[DickieG]

Right here we go... my car is the mk1 xantia 1.9td VSX with the hydractive 1(?) suspension, anyhow it has the button near the handbrake that supposedly makes the suspension soft/hard which as far as I understand is the difference between H1 and H2 where H2 is automatic with the switch making the soft sphere switch in sooner and holding it longer.

Just Hydractive 2 was fitted on Xantia's.

with Hydractive 2 the switch doesn't turn anything on or off really, all it does is alter the threshold at which the suspension switches from soft to firm.

So am I right in understand that when the switch is on, the electrovalves for the centre sphere should buzz (like it did in my previous xantias when the door was opened) when the sphere is not connected to the hydraulic circuit (i.e hard).

No, see above, opening a door on any Hydractive Xantia should turn the electrovalves on/cause them to buzz.

Now IF they are 'supposed' to make a noise, then obviously mine don't work, in which case I need to investigate more, there is only one obvious engine bay ecu in my car and it has the two plugs

Yes the Hydractive ECU is in the box close to the O/S headlight, it has one black and one white connector block.

Do these throw up faults too and resort to hard mode? Or could it be that it may not even be getting a power supply? Could it even be the the diode issue?

Yes to all of those really, make sure you check the fuse in the engine bay fuse box (IIRC number 17?)

Will disconnecting the battery reset the ECU to see if it goes soft, or do I need to actually clear the memory by means of a LEXIA unit or the likes?

Disconnecting the battery will not clear any faults which in some ways is a good thing because it means you can post your ECU to someone who has a Lexia/ELIT and they can "remotely" diagnose/clear the ECU for you provided they have a Hydractive Xantia to plug the ECU into.

I'm game on opening up the ECU if need be, but not until I get the basics looked at first, any ideas?

Check the fuse first, failing that post the ECU to someone (like me or Jim)

BTW if you decide to go looking for a ECU from a breakers, S1 and S2 Hydractive ECU's aren't compatible.

[Peter.N.]

If the ECU is working, providing all your spheres are OK, particularly the centre ones, you should be able to feel the difference in the suspension with the door open/closed. With the door closed you should have a couple of inches of up/down movement, with the door open five or six inches. This easier to feel on the back. If you shut the door and keep bouncing, you should feel the suspension stiffen after about a minute - when the buzzing stops.

The most common problem with the ECU is failure of the diodes across the electrovalves, if you are handy with a soldering iron you can fit a couple on the PCB. Assuming its the same as an XM, I have successfully done several on them.

Peter

[DickieG]

The most common problem with the ECU is failure of the diodes across the electrovalves, if you are handy with a soldering iron you can fit a couple on the PCB.

I'm not so confident its as simple as that Peter because if the diodes fail there's a very good chance that one of the VN05N's within the ECU will have been fried as happened to my HDi, after all the main purpose of fitting additional diode's is to prevent failure.

Here's a photo of the failed component,



As it happens I managed to source a replacement VN05N and soldered it in, however again its not so simple because after any such failure the ECU will register all manner of codes and end up locked into firm mode anyway, so unless you also clear the faults with a Lexia/ELIT/Proxia you'll be waisting your time thinking that soldering in diodes will sort it out.

[Peter.N.]

Well, I can only speak as I find and I have three cars with diodes fitted on which the suspension is performing perfectly - and it wasn't before. You could hear the solonoid valves engage but not disengage and the suspension remained hard. there was only one that it didn't cure and I fitted a pair VN05N's and that didn't cure it either so I binned that one. Do you think it would have worked if I had debugged it?

[DickieG]

Well, I can only speak as I find and I have three cars with diodes fitted on which the suspension is performing perfectly - and it wasn't before. You could hear the solonoid valves engage but not disengage and the suspension remained hard. there was only one that it didn't cure and I fitted a pair VN05N's and that didn't cure it either so I binned that one. Do you think it would have worked if I had debugged it?

The diode mod can help with how sharp the valves engage/disengage but the problem remains of the ECU recording faults so whilst you say the suspension is performing perfectly, personally I'd have my suspicions as any fault recorded with Hydractive 2 puts the ECU into a default mode and many others stuck in firm mode, how perfect can that be?

The ECU you repaired may well have worked again if the faults were cleared, the one on my HDi following repair did activate the valves but it had recorded every fault possible including a defective ECU so without a Lexia/ELIT I would have been lulled into thinking the ECU was working correctly when in fact it wouldn't have until the faults were cleared.

Since the repair/fault clearance its worked fine, albeit with the typical occasional recording of a steering sensor fault "As they all do Guvnor"

If you're unsure/inquisitive you're welcome to post ECU's to me for a diagnosis on my Lexia, I can plug them into one of my Xantia's to do the diagnosis which won't have an effect on the diagnosis as I wouldn't be driving the car, simply reading faults.

[lexi]

That board looks like the innards of a Hi fi cd player

[Peter.N.]

OK thanks. Well they are all working to my satisfaction at the moment, soft suspension, about 4-6 inches of movement with the door open, going hard, about 2" movement after about a minute or so when the valve closes. The only spare ECU I have was destroyed when my wife crashed the car.

[DickieG]

The point that you're satisfied with the way you cars are performing is the important one, enjoy!

[vince]

I need to get my rear suspension sorted again in the new year...

Ive no idea how my rear spheres are affecting it but i would put money on it that my rear centre is on its last legs....and the others not so far off either.

The system is great once its all cleared and working well.

[CitroJim]

Vince,

When I'm not busy breaking V6s and the like, take a pootle down this way and we'll sort you out It'll be a while yet though as I can't do anything now until I've completed the breaking and my drive is clear again.

Besides, I have a spare wheel carrier here for you

[deian]

Hi guys, thanks for the replies, apologies for being so long to reply myself.

Well I can't 'hear' the electrovalves. So I will check the fuse, silly me for overlooking that myself.

Should there still be no apparent life from the ecu then I may send it over to one of you guys after the new year. That would be much appreciated.

I'm may open it up to look at the diodes, I may attempt a repair if i feel handy with the iron over xmas.

I didn't know that about the ecu types on the xantia richard, thought early ones were H1 and later ones were H2, maybe that is just the case with the XM.

So the documentation I have for the H2 ECU will apply my mk1 Xant. Cool.

Thanks for your help.

[xantia_v6]

I'm may open it up to look at the diodes,

The diodes are not in the ECU, they are in the electrovalves. (which is why it is easier to add external diodes in case of doubt.

[deian]

ok, got my ecu off, gonna open it up, again, the citroen seals of life are annoying me (remember the fuel tank screw on lid under the rear seat).

i will have a quick look inside and if i feel any components need replacing i will do it first, then i will try it back on, but i would assume errors are recorded and the suspension is stuck in hard mode.

i also have the citroen technical guide here somewhere so i will look which cables go the e.valves and shove a diode into it too for good measure, may even get the LED mod done (u know make is show when it;s in hard or soft mode).

So is there anyone still up for plugging it into a lexia for me sometime soon? i will re-imburse for the effort obviously, let me know

thanks guys

[DickieG]

So is there anyone still up for plugging it into a lexia for me sometime soon? i will re-imburse for the effort obviously, let me know

I'm willing to do it for you, TBH it may be best to try that first before you start replacing components in case new components screw up the ECU in some way (not that I'm degrading your skills there you understand!).