Xantia II Hydractive Circuit Diagrams

addo · Unread post by **addo** » 30 Nov 2009, 06:45

Jim - any chance you would be able to load up the trio (location, schematic, symbolic) for Series II? I've saved the Activa ones you previously posted, but want to check some details against regular Hydractive II setout.

Thanks, Adam.

Unread post by **CitroJim** » 30 Nov 2009, 06:56

Hi Adam,

Yes, no problem at all. Will do that later this evening

AbangCorp · Unread post by **AbangCorp** » 01 Dec 2009, 02:33

gosh

this seems interesting

addo · Unread post by **addo** » 01 Dec 2009, 10:24

It is interesting!

• If Jim can find a few minutes to post up the other diagrams, I suspect there will be only one wire different - 7723, which goes from Pin 9 on the white suspension ECU plug to the Activa electrovalve (part #7718 on the Activa diagrams). The companion wire on that plug is a ground, spliced into the bolt-down ground terminal near the RH strut like all others.

• A resourceful person could probably modify the white ECU plug to accommodate this extra wire. As the plug's rear is encased in a sort of polyurethane/rubber sealant this would not be fast or easy.

• It seems reasonable to assume that the suspension ECUs are also extremely alike; Hydractive and Activa share the same inputs from identical components. I would not be surprised if the extra driver transistor(s) and other related components could be added, and the ECU re-flashed to Activa spec.

Yes, I am aware that the Activa harness/ECU has a different plug to prevent installing in a regular Hydractive setup, but perhaps (for the hobbyists) we are now looking at ways around this...

Unread post by **CitroJim** » 01 Dec 2009, 20:19

addo wrote: • A resourceful person could probably modify the white ECU plug to accommodate this extra wire. As the plug's rear is encased in a sort of polyurethane/rubber sealant this would not be fast or easy.

• It seems reasonable to assume that the suspension ECUs are also extremely alike; Hydractive and Activa share the same inputs from identical components. I would not be surprised if the extra driver transistor(s) and other related components could be added, and the ECU re-flashed to Activa spec.

Ahh, it's a lovely thought Adam and even though the solder pads on the PCB exist for the additional VN05 switch for the Activa stiffness regulator electrovalve, it won't work as the ECUs are one-time programmable only. If it's previously been programmed as a standard Hydractive ECU it can't be reprogrammed again to become an Activa ECU

Here's the circuits of the standard Hydractive setup...

MK2 Hydractive Circuit

MK2 Hydractive Harnesses

MK2 Hydractive Component Locations

Sorry one is a bit on the tilt

If I was scanning Activa circuits they'd have kept on the level

addo · Unread post by **addo** » 01 Dec 2009, 21:53

Ta for that - all filed away now!

This "non-rewritable" bit puzzles me. After all, quite a good number of people seem to make a habit of cracking software and overwriting stuff. The boxes are NFP now, so I'd have thought the need was gently rising...

Regards, Adam.

Unread post by **CitroJim** » 01 Dec 2009, 22:04

I'm sure if you put a really top-notch electronics whizzkid onto the job Adam, it could be done. I guess it all depends on what sort of PROM they have in them..

The Lexia won't reprogram them but that's not to say they definitely can't be of course but I don't know how to approach such a job unfortunately. The only electronics I'm really happy with and totally knowledgeable of has those quaint glass tubes called valves that glow in the dark.. Black, multi-legged devices on PCBs I never quite got the full hang of

Another difference with the pukka Activa ECU is that the black connector is replaced by a green one with different keyways.

I've used (as a test only) an Activa ECU in place of a standard Hydractive ECU buy gently cutting off the offending keyway. It works but I never ventured out on the road with it fitted.

addo · Unread post by **addo** » 01 Dec 2009, 22:18

You'd think the electronics required to drive it, if built solely with vacuum tube technology, might load up a decent sized box trailer nicely!

Or are 6L6s a straight swap for VN505s?

We're probably only a year or two from the point where a "prestige" maker has ICE featuring visible amplifier valves behind a glass screen in the console, just for the J Arthur factor. I'd say all that's stopping them so far is adequate shielding...

Jumping back to the present for now - I note the rear Activa electrovalve has a different part number - did you test the drive frequency/amplitude of this output during the probings some months back? Have to wonder if it's just spec'd different because of a different plug indexing slot.

Cheers, Adam.

Unread post by **CitroJim** » 01 Dec 2009, 22:34

addo wrote:I note the rear Activa electrovalve has a different part number

Ahh, now that's interesting Adam. All I do know is the Activa Electrovalve works in the opposite sense to the Hydractive ones. When the Activa electrovale is de-engergised the system is in "soft" roll correction mode as apposed to the hydractive ones that set hard mode when de-energised so maybe the electrovalve works in reverse to achieve this.

I'll have a gander next time I'm in the ECU box with a 'scope and I think I have an Activa sphere block knocking around so I'll have a look at the electrovalve.

addo wrote:You'd think the electronics required to drive it, if built solely with vacuum tube technology, might load up a decent sized box trailer nicely!

There was a valved fuel injection system marketed in the USA briefly back in the 50s, I believe called the Electrojector and made by Bendix. Likely that had a nice row of 6L6s driving the injectors

Must have been quite a task to generate the required HT for that lot though. Needless to say, it was not a success, not because it used valves so much but because the wax/paper capacitors had a tendency to develop leakage.

It seems bad enough waiting for IDI diesel glowplugs to do their thing but imagine having to wait for a valved fuel injection system to warm up before starting up!!!

Valved ICE in cars

You just know it will happen one day!!!

DickieG · Unread post by **DickieG** » 01 Dec 2009, 22:34

addo wrote:Jumping back to the present for now - I note the rear Activa electrovalve has a different part number - did you test the drive frequency/amplitude of this output during the probings some months back? Have to wonder if it's just spec'd different because of a different plug indexing slot.

The rear balancing electrovalve on an Activa works in reverse to the normal Hydractive blocks. i.e. normal Hydractive blocks default to firm whereas the Activa one goes to soft.

Unread post by **CitroJim** » 01 Dec 2009, 22:36

Richard, sorry

We must have both been bashing the keys at the same time there....

DickieG · Unread post by **DickieG** » 01 Dec 2009, 22:36

You beat me to it Jim.

DickieG · Unread post by **DickieG** » 01 Dec 2009, 22:37

Bloody hell that's twice in quick succession!!

addo · Unread post by **addo** » 01 Dec 2009, 22:43

I'm sort of bummed out the Activa electrovalve's a different beast by nature of its reverse operation. It crimps my local scrounging opportunities.

Unread post by **CitroJim** » 01 Dec 2009, 22:47

addo wrote:I'm sort of bummed out the Activa electrovalve's a different beast by nature of its reverse operation. It crimps my local scrounging opportunities.

You could always invert the signal to it Adam. A 6L6 would do that a treat