Abs Out Of Use Message

[kiwi]

Hello all,

It is winter time here downunder, and my S1 2.0sei, which normally spends the evenings in our garage, has been spending a lot of time out in the weather. Recently on startup in the mornings, it has displayed the ABS Out Of Use message, but then the message and the ABS light goes off and doesn't come on again until the next time I start the car.

So, my question is does this mean the ABS is actually out or is the electrical system just giving me a dodgy early morning message? I assume that the message would remain displayed if it was totally kaput - or am I assuming wrong?

Regards,
Kiwi

[techmanagain]

The display would indeed stay on to stress you if the ABS were out of order permanently - at least that is my understanding from experience. It is possibly the self-test by the computer getting warmed up slowly due - perhaps - to a dry joint in the cicuitry.

[Ciaran]

Hi Kiwi,

This is very common, with most XMs suffering it one time or another. There's plenty of documentation on the subject both here and on XM-L.
The general consensus seems to be that its caused by bad earth, or voltage drop to the ABS ECU. If the voltage is below a certain level, it will cause it to put the light on and display the message. The ABS will still work fine if you have cause to test it though.

My own S1 2.0SEI does exactly the same thing. Oddly though, mine displays the message far more on warm, dry days. It hardly ever does it when its cold and wet.

My S2 2.1TD gets the warning very rarely, normally when its been left parked on a hill, or when the rear offside corner has been jacked up (makes me suspect the sensor on that wheel doesn't like being left at certain angles).

Something you can try is replacing the old S1 earthing blocks, if your's still has them. This can provide improved earthing and may well resolve the ABS fault, as well as several other things. In my case though, replacing the earthing blocks with eyelet connectors actually made the problem much worse, I now get the message far more frequently than before, but hey what can you do

There's also a way of checking the ABS ECU for fault codes, in case your problem should lie elsewhere, but I'm unsure how unfortunately. Rest assured though, one of our more experienced contributors will be along shortly to impart that information!

Cheers

Ciarán

/EDIT: I started typing that ages ago and have only posted it, so missed techman's reply


This post has been edited by Ciaran on July 09, 2007 10:26 am

[kiwi]

Cheers, thanks - nice to have some reassurance. I guess it's like me and doesn't like being cold and damp. Mine has had the earthing blocks done by a previous owner, although I do get the odd spurious message about brake lights etc under certain conditions such as braking at night with an indicator going - even though the bulbs are fine. I guess thats a voltage drop thing also.

Pity there isn't a test button - it would be nice to be able to do a systems check on the display.

Regards,
Kiwi

[Ciaran]

I often get the brake light warnings when indicating too (It's also pretty common). I believe that system works by measuring the current or resistance in the brake light circuit, and the recorded value changes when a bulb stops working, hence it can detect the failure.

What seems to happen is parts of the circuit corrode, causing high resistance (or current drop, not sure which), resulting in false readings. A few people have managed to fix it by cleaning up the earths for the rear light cluster, and cleaning the contacts on the bulb mounts themselves. As with everything like this though, your mileage may vary.
An easy thing to try, mind you.

Someone, I believe it was Noz or Peter, mentioned about dreaming of doing diagnosis and displaying ECU running values and such through the dot matrix. I believe its possible on S2, as the display in those accepts external data (think that's how the radio displays the station name).
S1 displays don't do the station name display, so I'm not sure if the same scenario would be possible with them. A very interesting idea though.


Ciarán

[xmexclusive]

Hi All

The rear light earth problem is often real. One or other of the bulbs looses contact within its circuit for a short while. It happens to Mk2 cars as well as Mk1 it is just that on Mk2's you need to notice a bulb out which is difficult while driving. It is a little sad that Citroen never totally solved the problem but simply dropped the bulb test feature on MK2's. Poor/oxidised contacts on the rear bulbs/bulb holders are a common cause. Abrasive cleaning up without treating with a switch contact spray or similar will just encourage rapid return of the problem. The body earths on XM's, even when eylet type are electrically unsound unless the metal around the stud is cleaned down to bare metal to provide direct contact between the eyelet and the chassis. Otherwise the contact path is from eyelet to eyelet to the clamping nut and then via the contacting threads into the body via the stud. The tighter the nut is screwed down the smaller the thread contact area so this does not produce the expected increased contact path but it is not as bad as a corroded spade connector.

Regards

XMexc

This post has been edited by xmexclusive on July 09, 2007 02:03 pm

[Ciaran]

Hi XMexc.

That's certainly put an interesting slant on things. Do you think when the bulbs momentarily go out of circuit, this is due to them being loose, or is it more to do with the buildup of resistance becoming too much at certain times (i.e when other lights in the cluster get used, like indicators)?

I'll have to take a look at might light clusters, just as soon as the weather here in sunny Ireland stops being so fantastic.

Cheers!

Ciarán

[Assich]

On my first Mk2 I used to have to take the connector in the front wheel arch for each of the front ABS sensors apart and squirt with WD40 from time to time to cure this problem. I assume the Mk1 has the same connector. Common problem. They finally changed the location and type of connector in the later cars.

[techmanagain]

The brake light warning was a standard fault on the St - generally rectified by tapping into the realamp earth wire (Scotchlock) and fitting an eyelet to slip under the nut on the rear light securing stud.

[citroenxm]

Hi All

Interesting title this one.. My S1 1993 V6 SEi, has also suffered from the dreadded ABS OUT OF USE message, but it has STILL WORKED with the message on..

Anyway, I have finished installing the replacement auto box job, and had an MOT booked, but the message and light still on, and of course can be a fail with it on, so I tried to work out what to do...

I ended up disconnecting the orange light warning, in the clocks section and hey presto the message ALSO went out!!, and the best bit, the ABS ALSO STILL works too, I just dont get a check light come on... you know mr MOT man, blown buld possibly??

Anyway, sent in for MOT and result? Oh yes, A nice new MOT!!

(See my new post, cooling fans problem, please)

REgards
citroenxm

[aengus-xmv6]

on the earlier ABS system (Bendix), another fail point is the black module on the ABS block - one pin on the block that is all common earth seems to lose the solder bond and makes intermittent contact, giving "ABS out of use" every now ang again when driving.

Cure -
remove from car (no need to take the valve block out, just the module by disconnecting the cables and 3 small bolts - oh, and 2 philips screws holding the valve connector.

Open unit up, watch you don't break the diode, resolder the joints, reassemble and waterproof (sealant & self-amalgamating tape) and away you go.

Alternatively, a peg between the connectors will put enough force to 'make' the connection and seems to work too - someone else's suggestion.

regards
Dave