Xantia ABS problem, SOLVED

Mads · Unread post by **Mads** » 09 Jul 2007, 21:27

Hi forum users,

I have been renovating my brakes front to back (Front disks, pads, rear pads + "corrosion", + new front brake hoses), and not they are realt nice and sharp. Think the rear renovation did the largest difference.

Had a problem with the left brake hose, simply could not get a spanner at the inner nut, gearbox/driveshaft in the way

. So decided to have a garage with a lift change that one and they did, only to have the same trouble and when the smoke cleared they ended up having changed both front brake pipes (Don't ask me how it got that messed up). Fortunately they footed that part of the bill themselves.

Well so fare so good, but today I noticed that the ABS doesn't work, i.e. I can get the front wheel(s) to lock

, and no "ta-ta-ta-ta-ta-ta" sound. The warning light doesn't com on (bulb is OK). Had both sensors out for a good clean, no improvement, and the wires seem OK. Last thing I can think of is that the garage swapped the new brake pipes at the ABS-unit, so that the left output now goes to the right hand brake and visa versa. The effect would be that when e.g. the right wheel starts to lock, the ABS will lover the pressure as it should, but because the pipes are swapped, it will be the left wheel that reduce braking.. Results should be that one wheel locks up, and the other doesn't brake at all

This seems to be exactly what is happening judging from the burned rubber marks on the test-strip

So; Is there anyway to tell which pipe goes into which hole in the abs.-unit ? Does anyone have an alternative idea of what the problem could be? Help will really be appreciated as the whole family is of to France on Thursday, and I do not really want to risk the whole "gene-bank" in anything less than a car in mint condition. Thanks in advance. 8)

++++

The new brake pipes were swapped

Won't be using that garage any more

For future reference: On the ABS-unit on my car, the top pipe goes to the left fron wheel and the mittle pipe to the right front wheel.

Thanks for all the help

Mandrake · Unread post by **Mandrake** » 09 Jul 2007, 23:07

Mads wrote:Had a problem with the left brake hose, simply could not get a spanner at the inner nut, gearbox/driveshaft in the way . So decided to have a garage with a lift change that one and they did, only to have the same trouble and when the smoke cleared they ended up having changed both front brake pipes (Don't ask me how it got that messed up). Fortunately they footed that part of the bill themselves.

So let me see if I have this straight - you asked them to change the brake "hose" on the left, eg the flexible hose in the wheel arch ? But they also changed the steel brake lines to the ABS block ? Why ????

Honestly doesn't make any sense to me.

Well so fare so good, but today I noticed that the ABS doesn't work, i.e. I can get the front wheel(s) to lock , and no "ta-ta-ta-ta-ta-ta" sound. The warning light doesn't com on (bulb is OK). Had both sensors out for a good clean, no improvement, and the wires seem OK. Last thing I can think of is that the garage swapped the new brake pipes at the ABS-unit, so that the left output now goes to the right hand brake and visa versa. The effect would be that when e.g. the right wheel starts to lock, the ABS will lover the pressure as it should, but because the pipes are swapped, it will be the left wheel that reduce braking.. Results should be that one wheel locks up, and the other doesn't brake at all This seems to be exactly what is happening judging from the burned rubber marks on the test-strip

Hmm, while I follow your reasoning I don't know that this is whats happening - while its certainly true that mixing up the pipes would dramatically stuff up the effectiveness of the abs, I would have thought you would still feel pulsing on the pedal ?

Do you see the ABS light come on and then go out when starting the engine as it should ? Does the light stay on if the ABS computer is unplugged and then the engine started ? (It should)

So; Is there anyway to tell which pipe goes into which hole in the abs.-unit ? Does anyone have an alternative idea of what the problem could be? Help will really be appreciated as the whole family is of to France on Thursday, and I do not really want to risk the whole "gene-bank" in anything less than a car in mint condition. Thanks in advance.

The only way to tell would be to compare it with another car, or if you're convinced that they have been swapped over, trace the pipes carefully and swap them and see what happens...(and make sure to swap them back if it doesn't help)

Regards,
Simon

AndersDK · Unread post by **AndersDK** » 09 Jul 2007, 23:21

Hej Mads -

Driving to France in such a car could be more entertaining than you really want - *yuk*

If you can not get the car booked for swapping back the pipes before leaving to France, then you have these options :

1) rent a different car

2) postpone your trip to France

3) find another garage

4) do the pipework yourself

5) swap the connectors from the sensors, where suitable

6) remove ABS fuse

Your Xantia is in no way dangerous to drive without ABS function 8)
Lots of cars on the roads still have no ABS system fitted. They just lack that 5% extra safety you need once in your lifetime when things all adds up against you.

But it certainly is VERY dangerous if the ABS system is working erratic

In that situation I'd not hesitate to rip the fuse. Not even a split second

jeremy · Unread post by **jeremy** » 09 Jul 2007, 23:46

The ABS warning light should come on when you turn the key or start the engine then go out. This is the normal self test and is probably an electrical continuity test. Once the light has gone out the system will continue to monitor until it is turned on by pressure on the brake pedal (usually the brake light switch)

If the light isn't coming on then the ABS unit won't be doing anything. Its a fundamental connection problem - not sensors - as if there is anything wrong with them the light will come on. If you look at the wiring diagram you will find that there are a number of power sources to the unit - and for example fuse failure will cause the light to come on.

Mads · Unread post by **Mads** » 09 Jul 2007, 23:48

Thanks for the replies !

Brake pipes were changed becaurse they could not undo the hose-nut (same problem I had), and they therfore had to cut the pipe. Why both pipes were changed...?!!? beets me.

, but then again; I have been there myself

Thanks to Anders for the options. In case I fail to solve the ABS puzzel, I'll pull the fuse, but I would really like to have a working ABS onbord. I thourght about just swapping the ABS sensor connectors, but I'm not sure that is possible, I'll have a look tomorrow. Otherwise I'll try swapping the new brake pipes at the ABS-unit and see if that solve the problem, but if anyone knows which wheel goes into which hole I would really like to know !!

Mandrake · Unread post by **Mandrake** » 09 Jul 2007, 23:49

AndersDK wrote:5) swap the connectors from the sensors, where suitable

I don't think this is possible on the Xantia loom. The main loom from the ABS computer splits in left and right directions on the chassis before single plugs to the sensors are reached - the left sensor cable can't reach the plug for the right one...

6) remove ABS fuse

Your Xantia is in no way dangerous to drive without ABS function 8)
Lots of cars on the roads still have no ABS system fitted. They just lack that 5% extra safety you need once in your lifetime when things all adds up against you.

But it certainly is VERY dangerous if the ABS system is working erratic
In that situation I'd not hesitate to rip the fuse. Not even a split second

Absolutely true - if there is any doubt about the safe operation of the ABS it is safer to simply remove the ABS fuse, (until fixed) and now you have a perfectly standard non-ABS braking system.

Regards,
Simon

Mads · Unread post by **Mads** » 09 Jul 2007, 23:51

To clarify: The ABS light does come on when I start the car and dissapear after af couple of seconds.. exactly as it have done for the last ten years.

jeremy · Unread post by **jeremy** » 10 Jul 2007, 00:05

I see that Haynes doesn't have a diagram showing which pipe goes where. You know the 2 suspect pipes - do you know anyone with a similar car you could inspect?

Have they used genuine Citroen pipes? The reason I ask this is the genuine pipes are a real work of art and are very carefully bent to shape. If genuine ones have been used it may be that on inspection you can see that they have been forced to fit. If they have made their own pipes this won't show.

Mads · Unread post by **Mads** » 10 Jul 2007, 00:24

I looked in Haynes, but no real help, as there, like Jeramy says, is no diagram of the hydraulic system.

The garage made their own cupper pipes. Nice and durable I'm sure, but no way a work of art!

Unfortunatly I don't know anybody who own a simmilar car, so I guess I'll just have to bring out the spanners tomorrow and give it a go..

AndersDK · Unread post by **AndersDK** » 10 Jul 2007, 01:59

Mads - you have mail.

Unread post by **RichardW** » 10 Jul 2007, 10:39

I'm happy to photograph the ABS block on my 97 TD if I can and it's any help? Never looked at the Xantia one, but the ZX (Bosch) one is clearly marked which port is which. Actually isn't there a pipe connector block on the firewall that the brake pipes go to before they get to the ABS block?

AndersDK · Unread post by **AndersDK** » 10 Jul 2007, 11:46

Mads wrote:++++

The new brake pipes were swapped Won't be using that garage any more

For future reference: On the ABS-unit on my car, the top pipe goes to the left fron wheel and the mittle pipe to the right front wheel.

Thanks for all the help

Have a nice trip to France Mads

Of course we can NOT take this misshap as a general indicator for workmanship in a Citroen garage.
But shame on them, that they did not at least test the car before handing it over to the owner

The car was in fact a death trap to drive in, whenever some serious work put on to the brakes

Darko · Unread post by **Darko** » 10 Jul 2007, 12:45

Mandrake wrote:Hmm, while I follow your reasoning I don't know that this is whats happening - while its certainly true that mixing up the pipes would dramatically stuff up the effectiveness of the abs, I would have thought you would still feel pulsing on the pedal ?

IMHO You wouldn't, because the ECU thinks the wheel is still locked and doesn't "disengage" the valve until the wheel starts rotating again (which is never, because it's controlling the wrong valve).

Mads · Unread post by **Mads** » 10 Jul 2007, 22:46

Thanks again to everybody for your keen help. Glad the issue is solved and that the car now is in real good condition.

I'm still having shivers down the back though, thinking about the trouble such "workmanship" can cause less suspicious (and mechanically minded) people..

Now, I'm just looking forward to go the home of Citroën and enjoy a few of the other pleasures they excel in down there 8) If we spot one or two beauties with just the right curves on our journey, I'll be sure to post pictures for you all to enjoy.

Best wishes for a nice and relaxing summer to you all (and winter to Mandrake!)

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Xantia ABS problem, SOLVED

Xantia ABS problem, SOLVED

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