Xantia wiring inside ECU box help needed

Post by **ekaftan** » 23 Sep 2006, 23:44

Remember the Xantia with the lost code? I bought it anyway. Yes, I am mad. Already knew that. But it was the cheapest Xantia I could find that passed the local equivalent of the MOT and that had everything in working order.

or so I thought....

After driving it a couple of miles I realized the Hydractive was stuck in hard mode. I read a couple of pdfs I have been collecting for the last year (I have another Xantia but my wife calls it hers and wont let me have it) and can not find how to fix the problem...

First order of business: fix messy wiring inside the ECU box. Somebody
jumped one wire from the engine ECU to one wire in the Hydractive ECU. There is also a dangling relay inside that my other Xantia has fixed in a bracket. So two questions: Whats that relay for? and Where should I start looking to fix the suspension not having access to an ELIT box?

Thanks.

Mandrake · Post by **Mandrake** » 24 Sep 2006, 00:56

Oh boy,

where to begin.... there are a few threads covering this if you can dig them up, but the first thing I'd be checking is whether there is any power to the electrovalves. With the engine idling and a multimeter with a sharp pointed probe (or just use a pin) stab through one of the white wires in the picture below:

(By the way the wires are shown tinned as that picture was part of a how-to on connecting diodes there, just ignore that...)

And measure from there to earth. You should find an average DC reading of about 3 volts. (It's actually a 1Khz pulse width modulated signal)

Alternatively you could use an LED with a 100 ohm resistor.

One white wire is the front electrovalve and the other is the rear. (They're on seperate circuits, but switch together) You can't just unplug the electrovalve and measure there, because the computer detects a faulty electrovalve and shuts the output down.

If that seems ok the next thing to do is check and replace the Hydractive centre spheres, as if they are punctured it will seem to be in hard mode all the time. (Switching a sphere with no gas left into operation wont make much difference!!)

You shouldn't need an ELIT system to diagnose the Hydractive system unless it has a very obscure problem. A lot of diagnosis can be achieved with a simple LED connected to the electrovalve control wire located in view in the cabin when driving, plus an understanding of what the computer SHOULD be doing when it's working...(eg under what conditions should it be hard or soft)

Regards,
Simon

Post by **ekaftan** » 24 Sep 2006, 01:20

Mandrake wrote:Oh boy,

where to begin.... there are a few threads covering this if you can dig them up, but the first thing I'd be checking is whether there is any power to the electrovalves.

I am pretty sure there is no power to the electrovalves at all. I cannot hear them buzzing at all. Spheres do have some gas inside left because car does the '1 foot jump' when its doing citrobatics and I stop the engine and restart it.

What wire should I check to see if there is power to the Hydractive ECU?

A very bad sign: Fuse 8 (manual says its for the hydractive ECU) has been replaced with a 25 amp fuse. Should be 5 amp.

Another question: which wire is the one coming from the doors? The car has an aftermarket Alarm hacked in. Maybe the ECU never sees a door opening and never arms?

I also cant find the inertial switch. 94 Xantias had it? Maybe thats what the jumper is for...

Post by **ekaftan** » 24 Sep 2006, 01:27

ekaftan wrote:
I am pretty sure there is no power to the electrovalves at all. I cannot hear them buzzing. Spheres do have some gas inside left because car does the '1 foot jump' when its doing citrobatics and I stop the engine and restart it.

Its kind of lame quoting myself, but from your answer and now mine I now thing the ECU is powering up (valves click when key goes to run) but then
it no longer activates them.

Maybe its just that they dont measure the 4ohms they should. If I'm lucky its just a wiring issue...

I am still puzzled by the jumpered wire though...

Post by **ekaftan** » 24 Sep 2006, 01:53

ekaftan wrote: I am still puzzled by the jumpered wire though...

I am shocked. I will have to confirm it tomorrow with daylight, but I am pretty sure the jumpered wire is one of the white ones.

That would explain the jump when the key goes to run... one of the valves
is getting 12 volts directly.

I hope the ECU or the valve did not burn by the direct 12volt feed....

Mandrake · Post by **Mandrake** » 24 Sep 2006, 06:50

Ok, in answer to all your points in order:

If it does the "1 foot jump" then there must be some gas in the middle sphere for the end(s) where it jumps.

The Hydractive fuse on my car is 20 amps not 5, remember that most fuses do double or triple duty and power several systems, and the book you have might not be quite the right one for your model varient.

For the wire to the door switches, the 4 passenger door switches are connected together to pin 7 of the white plug, while the tailgate switch goes to pin 6 of the white plug.

However this isn't your problem because all this affects is the "anti-jolt" system which turns the electrovalves on when the doors are opened. When you're driving naturally the doors are closed so this has no effect on the driving characteristics.

Inertial switch ? Don't know what you're refering to there...there isn't one related to the suspension.

If the electrovalves briefly activate (click) when you open a door or turn on the key, but dont buzz/whine, its probably the computer detecting a fault - they should both measure around 4 ohms. You can check this from the computer end of the cable as well by unplugging the white plug - pin 1 is the front electrovalve positive, pin 2 is the rear electrovalve positive, and pin 8 and 15 are earth.

Another thing that can go wrong is there is a back EMF (reverse connected) diode built into the electrovalve coil unit, and these can go open circuit. If that happens it will also upset the computer and prevent it from keeping the electrovalves on.

You wont be able to test the diode with a straight ohms check as the 4 ohm coil resistance will shunt it. What you can do is supply 12v to the electrovalve *VIA* a 15 ohm 10 watt resistor and measure the voltage across the electrovalve.

If the diode is good you'll measure about 3 volts the right way around and less than 1v if you reverse the polarity of the supply. If its 3v both ways around the diode is faulty.

I hope you're not right about someone jumpering 12v to one of the white wires, if they have its highly likely to have burnt out the electrovalve, they can only stand about 1 minute of full 12v before they get extremely hot.

In normal operation they are supplied full 12v for half a second to switch them quickly and reliably (they wont switch with 3v) which then drops to 3v to maintain it in an on state with minimal power dissipation.

Regards,
Simon

Post by **ekaftan** » 24 Sep 2006, 12:52

Mandrake wrote: Inertial switch ? Don't know what you're refering to there...there isn't one related to the suspension.

The inertial switch is the name in the book for the round switch near one
of the strut tops that removes power to the engine ECU when you have
a crash. My 96 has it but the 94 has not.

My actual theory is that some backyard mechanic was looking for an earth wire and used the white wire. The valve still works (clicks) when the ignition
is turned on, so maybe there is hope.

Mandrake · Post by **Mandrake** » 24 Sep 2006, 20:24

Ah that switch. Yes my car has one....

I always thought it was an inertial fuel cutoff valve, to help prevent engine fires after a crash.

In any case its not related to the suspension

Regards,
Simon

Post by **ekaftan** » 24 Sep 2006, 23:18

Mandrake wrote:Ah that switch. Yes my car has one....

I always thought it was an inertial fuel cutoff valve, to help prevent engine fires after a crash.

In any case its not related to the suspension

Regards,
Simon

It does cut fuel... and according to my wiring diagram is connected to
the ECU.

Anyway... I took some pictures today. I am not at home and dont have the appropiate drivers to download them but will later.

The jumper is a blue wire that connects one of the two white wires on the rear Hydractive ECU connector to a rather thick red wire on the engine ECU (magnetti mareli) wiring.

There is a second jumper, this time white, from the same white wire on the Hyd. ECU that gets lost inside the wire loom.

I will post the pictures in a couple of hours to see it you can help me guess it they are there for some purpose or if I can just yank them out and see if the valves start working...

Post by **ekaftan** » 25 Sep 2006, 01:18

Link to pictures of the wiring mess:

http://www.nn.cl/Fotos/Autos/Xantia/LJ/

this one is a good summary:

Any ideas?

Post by **xantia_v6** » 25 Sep 2006, 07:00

Just in case you have not noticed, the woven tape (with red stripe) that is covering some of the harness does not look original, and it looks like there is more bodged wiring going on underneath it.

It is difficult to know why the wiring has been vandalised like this, and it may be that this was done to 'fix' some hidden problem in one of the hydractive components, and that this problem might still be present?

If faced with this problem, I would try to find a set of the components and harnesses from a scrap car, and rebuild the system with assumed good parts, as it is, you don't know how many faults you are chasing.
Mike

Post by **ekaftan** » 25 Sep 2006, 13:23

xantia_v6 wrote:
If faced with this problem, I would try to find a set of the components and harnesses from a scrap car, and rebuild the system with assumed good parts, as it is, you don't know how many faults you are chasing.
Mike

There are very few scrapped Xantias where I live (southamerica) so fiding items like wiring and ECUs is nearly impossible.

Next year I'll try to make a trip to the UK and hit the scrap yards

For now, I'll try and rebuild this and try to get somebody to sell me what I need from this list

Anyone of you wiling to sell me some parts bought off breaked Xantias?

andmcit · Post by **andmcit** » 25 Sep 2006, 13:59

ekaftan wrote:
xantia_v6 wrote:
If faced with this problem, I would try to find a set of the components and harnesses from a scrap car, and rebuild the system with assumed good parts, as it is, you don't know how many faults you are chasing.
Mike
There are very few scrapped Xantias where I live (southamerica) so fiding items like wiring and ECUs is nearly impossible.

Next year I'll try to make a trip to the UK and hit the scrap yards

For now, I'll try and rebuild this and try to get somebody to sell me what I need from this list Anyone of you wiling to sell me some parts bought off breaked Xantias?

I've been looking out for you anyhow - none around at the moment!
Time will tell though, I got one for a CT Activa with a code the other day
through ebay!

You are looking for a 8v 2.0i AUTOMATIC!?

Andrew

Post by **ekaftan** » 25 Sep 2006, 14:02

andmcit wrote:
I've been looking out for you anyhow - none around at the moment!
Time will tell though, I got one for a CT Activa with a code the other day
through ebay!

You are looking for a 8v 2.0i AUTOMATIC!?

Andrew

Yes... I have two of those, a 94 and a 96 ...

Is the Hydractive ECU cheap to buy at a scrapyard?

andmcit · Post by **andmcit** » 25 Sep 2006, 14:17

I guess so in my experience BUT getting one with a code is more of a
challenge as many are locked out and don't require a code input...

One thing to bear in mind is auto Xantia 2.0i's aren't a widely sold car in the
UK with the majority being diesel or 1.8 petrols. I actually bought a complete
running and MOT'd 2.0 VSX manual for the same value of an ECU earlier in
the year mind! What other parts do you need?

Andrew

French Car Forum

Xantia wiring inside ECU box help needed

Xantia wiring inside ECU box help needed

Pictures