Hydractive electrovalves

Toby_HDi · Post by **Toby_HDi** » 24 Jan 2010, 19:27

Many thanks to DickieG for taking a look at my Activa yesterday afternoon, hope I didn't take up too much of your time.

I'm popping this here as it's not solely Activa specific though I'm sure there are some differences. If its not appropriate I'll move it to the Activa area.

Spheres were tested and some found to flat, one or two were ruptured. New accumulator is a priority and I need to try to remove the Activa accumulator as we couldn't shift that one. I've been delving into the world of substituting spheres as I believe the Activa ones are difficult to obtain. It seems I can get them all with the exception of the Activa accumulator. Anyway, all four corner spheres are fine so will change the ones I need to and change the LHM for some hydraflush at some point soon as it looks a bit dirty.

The main problem discovered was that the electrovalves seem to be faulty. On the Lexia the front was being energised but the rear seems dead. The car is stuck in firm mode. Richard kindly carried out the diode fix and after this we could hear the valves positively clicking but there was no buzz from them. Basically I'm just after suggestions as to a route to take from here. It was suggested I may have to remove the electrovalve to investigate but we shall see. Could a flat centre sphere cause the valve not to work? The rear one is flat but as pointed out by Richard, it may not be worth changing it until the electrovalve is sorted, unless the flat sphere is the issue.

On a more positive note I am hugely impressed with the CT engine. I'm very much a V6 man but the CT has bowled me over with its torque and flexibility. Overtaking is effortless whereas I'm used to having to change down.

Even though the suspension is not fully sorted I'm loving the Activa system. Like it's on rails is the best way to describe it so I can only look forward to what its like when its all sorted. I'm absolutely loving Activa ownership

Post by **CitroJim** » 25 Jan 2010, 08:56

Hi Toby,

Delighted you're enjoying the Activa. You are seeing the charm of the CT engine

It is a bit of a torque monster!

Sorry it's taken a long time to get a reply together for this

Been busy

Right, first off, to all intents and purposes you can use normal Hydractive spheres for the corners and hydractie centres. The difference is pretty minimal. Accumulator is standard Xantia. The Anti-sink sphere can be replaced with a standard one as well.

I use standard Hydractive spheres on mine...

The two tricky ones are the Activa Accumulator and the Activa Balancing Sphere. The former is physically the same as an anti-sink sphere but is blown up to 62 bars. Best way to obtrain one is to ask Pleiades to regas an anti-sink sphere. The Activa Balancing sphere is a normal accumulator physically but at a much lower pressure. Again, Pleiades can make one from any accumulator or choose a weak accumulator or rear hydractive centre that is showiung about 30 bars pressure.

The electrovalves are an interesting problem. I believe your front one is OK and that one is humming and clicking normally but the rear I understand is dead. I had a long chat with Richard about it and even if the centre sphere is dead flat, the valve should still hum. My diagnosis is that either there is a wiring fault or the valve coild has gone short circuit. My method of testing will be to disconnect the wiring to the suspect valve and connect it to a loose test valve I have. If it then hums, it will then be known the valve has a duff coil. Hopefully, I have enough bits to make a repair. We'll need to remove your spare wheel cradle to get at it easily so if you can get some Plus-Gas working around ythe 13mm bolt the cradle hinges on, that'll help tooo...

A nice job for Sunday... Richard has suggested ways of loosening the Activa Accumulator as well. Keep dousing it with Plus-Gas if you can!!!

Xaccers · Post by **Xaccers** » 25 Jan 2010, 09:28

Jim, if Toby's coming up on Sunday, would you like me to check if Finmere is available?

Post by **CitroJim** » 25 Jan 2010, 09:51

Xac wrote:Jim, if Toby's coming up on Sunday, would you like me to check if Finmere is available?

We'll have a natter about that as there is a danger of Sunday turning into an FCF mini-meet as Paul (Citroenxm) will also be with us

Xaccers · Post by **Xaccers** » 25 Jan 2010, 10:13

The paint chuckers are about, don't know how long for but we should be ok in the car park as long as they don't park in front of the ramps.
I might see about popping alon on the Saturday to fence off some space for us.

Toby_HDi · Post by **Toby_HDi** » 25 Jan 2010, 19:57

Thanks fellas.

Does any one have Martin's contact details? Just in case that Activa accumulator is flat I'll ask him to blow up an anti-sink. Will also get the other spheres I need too. Definitely need an main accumulator anyway.

I'll plusgas that sphere and the cradle. Think I've got some left.

The front electrovalve clicks but it doesn't hum. I believe the rear is the same though that wasn't showing any activity on the Lexia whereas the front was.

Post by **CitroJim** » 25 Jan 2010, 20:00

Hi Toby,

Here's the contact details for Pleiades...

Looking forward to seeing you and car on Sunday

DickieG · Post by **DickieG** » 25 Jan 2010, 20:46

To explain further on Tobys Activa, I fiited a spare/partially deflated (30 bar) centre sphere to the rear Hydractive/Activa block, the rear standard Hydractive sphere is flat. Front Hydractive is OK, accumulator flat, front Activa sphere unknown due to being stuck to its mount/didn't want to break the mount. All four corner sphere's are OK.

Lexia diagnosed the rear Hydractive valve as having a permanent fault which will not clear, the ECU therefore reverts to its default state of firm suspension as a faulty electrovalve is determined as a serious fault. Fitting three additional diodes made no difference (logged fault still wouldn't clear after fitting the diodes) when opening a door the front valve can be heard clicking open but does not hum thereafter (more than likely due to the ECU going into default firm mode). When observing the operating perameters of the Hydractive system the system does try to occasionally reset itself by very briefly going into soft mode but instantly reverts back to firm mode.

Access to the rear Hydractive Activa block is poor to say the least, it will improve with the spare wheel carrier removed but even then it looks difficult.

One further point to note is that the Hydractive ECU had been accessed twelve times previously so clearly someone in the past has been having a poke around

Toby_HDi · Post by **Toby_HDi** » 25 Jan 2010, 21:17

Thanks for that Jim, I'll have a chat with him about sourcing an Activa Accumulator.

Richard, thanks for explaining a few things abit more clearly than I could

Mandrake · Post by **Mandrake** » 26 Jan 2010, 09:24

DickieG wrote: Lexia diagnosed the rear Hydractive valve as having a permanent fault which will not clear, the ECU therefore reverts to its default state of firm suspension as a faulty electrovalve is determined as a serious fault. Fitting three additional diodes made no difference (logged fault still wouldn't clear after fitting the diodes) when opening a door the front valve can be heard clicking open but does not hum thereafter (more than likely due to the ECU going into default firm mode).

Try disconnecting the rear electrovalves and in their places connect resistors of approximately 100 ohms. (5 Watts) This will fool the ECU into thinking the rear electrovalves are ok, assuming the wiring harness is ok as well.

Now test the front to see if the front electrovalve is remaining on and try bounce testing the front suspension as well.

Also place a multimeter in DC mode across the resistor for the rear hydractive block and when you open the door you should see a half second period of 12v, followed by a continuous reading of about 3.3 - 4.5 volts. This is actually a pulse waveform not DC so depending on your meter it may read slightly differently, but it should be somewhere in that region.

Assuming you see this reading, (and the front suspension was working) you now know the ECU and wiring are ok and that it must be the electovalve itself.

I don't think you'll see any reading on the Activa electrovalve as I believe it's off by default - Jim would know

It's possible to test the internal diode and the coil in the electovalve with a very simple rig, (best done when the electrovalve is out of the car) all you need is a 12 volt supply and a 22 ohm 5 watt resistor.

Set up a rig so you have a volt meter connected across the electrovalve, and then connect the electrovalve in SERIES with your 22 ohm resistor to the 12v supply. (Do not connect it directly) Note the voltage reading. Now reverse the polarity of the supply and measure again.

In one direction the voltage will be low - about 0.7 volts, this is reverse polarity and shows that the diode is working. The other direction is the correct polarity and the voltage should be 2-3 volts. (If I have remembered the resister value correctly...it might have been 18 ohms..)

When the voltage is connected the right way around via the resistor, momentarily bridge out the resistor and the electrovalve should clunk solidly, and then remain latched after you unbridge it - it should stay latched until you remove the supply, but don't run it for more than a few seconds at a time.

When observing the operating perameters of the Hydractive system the system does try to occasionally reset itself by very briefly going into soft mode but instantly reverts back to firm mode.

Yes, it checks once per minute by attempting to energize the electrovalves, if one or more are faulty it will drop out again.

Regards,
Simon