Xantia MK2 abs question

[Chris570]

Evening all,

Can someone with a MK2 xantia pretty please check if their pin 24 on the abs multi plug has an earth connection on it..

The reason for asking is I am looking at an abs fault and I have diagrams showing an earth on pin 24, but nothing physically in there.

Very much appreciated!

[xantia_v6]

There were updates to the ABS during production. What is the RP for that car? Maybe I have the correct diagrams.

[Chris570]

I don't have the rpo unfortunately, however it was registered in Nov 1997

[xantia_v6]

Does it have 25 or 37 pins on the ABS module connector? It looks like early S2 cars had the same ABS as late S1 cars.

[Chris570]

It's the 25 pin connector

[xantia_v6]

Thats strange. The 25 pin connector version was introduced at RP 7668, February 1998. All the diagrams I have here show pin 24 connected to ground.

FWIW, this is the diagram of the 25 pin version from RP 7668:



and this is the version with 37 pin connector, RP 7483 until 7667

[CitroJim]

Hi Chris, Good to see you and a very Happy New Year... Don't be a stranger, we need to catch up

[Chris570]

Hi Chris, Good to see you and a very Happy New Year... Don't be a stranger, we need to catch up

We certainly must!!

Thank you for that info..... our original thinking was that we were missing an earth on pin 24, the plug we have (from a xantia mk2) has the earth on pin 9, adding an earth to pin 24 (and also removing it from 24) doesnt fix the issue, we think that's internally bridged.....

This is an odd one. We are fitting the ABS system to another car (LHM Blooded). The wheel sensors are the Xantia MK2 type. The Hubs are from a XJ40. We can talk to the ABS ecu with a Lexia, and that shows the wheel's spinning when they should etc. It also shows no faults.

The only fault we have is that the ABS light comes on solidly for 2-3 seconds on ign on, and then it will flash quickly. A little light googling suggests this is failing a self test. We've also plugged another ECU in and it does the same thing. The ABS does not work when you stamp on the brakes (but it was tested at walking speed, which I don't believe it would activate at anyway?)

We've wired it up exactly the same way as per the diagram with one difference, we've put a bulb on the ABS light side, with a switched 12v one one side, and the ABS block on the other side. Upon closer inspection of the diagram we can see that actually the dash cluster seems to have some communication with the ABS block on pin 15. We're now trying to see if we can partially reinstate the dash cluster to make the ABS block happy.

Does anyone have any insight as to what communication might be happening on that pin? (Otherwise we'll have to swap over to a MK1 system, which will be a pain in the backside as the car is already piped for this one...)

[Chris570]

Update for those of you mad enough.....

We have got it to work, we've wired in the Xantia dash clocks (sans needles etc) and now all plays well. The ABS light behaves exactly as it should (it passed Government inspection!). The ABS system also functions correctly now.

We still don't know *how* the ABS ECU is being told all is well and *how* it communicates to the dash clocks to tell it to function, but it does.

After some more tinkering we'll figure out how it does it. I'll update here how it goes as I suspect that as the Xantia gets older and spares get harder to find, info like this could be very useful to someone.......

[CitroJim]

Pleased all is now good Chris It really is a conundrum and I'll be interested to learn the reason in due course...

[Chris570]

Pleased all is now good Chris It really is a conundrum and I'll be interested to learn the reason in due course...

We'll have to sit down for a big tea session..... There's so much to tell!

[CitroJim]

Pleased all is now good Chris It really is a conundrum and I'll be interested to learn the reason in due course...

We'll have to sit down for a big tea session..... There's so much to tell!

That'll be good Chris, will be looking forward to it

[Michel]

This is an odd one. We are fitting the ABS system to another car (LHM Blooded). The wheel sensors are the Xantia MK2 type. The Hubs are from a XJ40. We can talk to the ABS ecu with a Lexia, and that shows the wheel's spinning when they should etc. It also shows no faults.

I'm *dying* to know what on earth this vehicle is.

[Chris570]

This is an odd one. We are fitting the ABS system to another car (LHM Blooded). The wheel sensors are the Xantia MK2 type. The Hubs are from a XJ40. We can talk to the ABS ecu with a Lexia, and that shows the wheel's spinning when they should etc. It also shows no faults.

I'm *dying* to know what on earth this vehicle is.

No need for dying, but I shall reveal here.

It's a Cobra Replica, AK chassis.

It differs slightly from the standard (if there is such a thing) build.

It is Xantia V6 powered, with side pipes and custom manifolds (they sound amazing!)
Cosworth 5 speed manual gearbox, XJ40 Rear axle.
Xantia rear rams turned upright to behave like a coilover with remote spheres.
Hydractive 2
Xantia Braking system including the ABS.