Fitting an ABS ECU

KevMayer · Unread post by **KevMayer** » 15 Feb 2006, 23:21

Have you tried braking hard to see if the wheels lock up and the car skids.
This must be the easiest way to test whether the ABS works.

Cheers,

Kev

steviewonder7 · Unread post by **steviewonder7** » 16 Feb 2006, 09:27

I have braked hard on a few occations but dont feel the abs has come into action.
I have a reasonable feel of how the abs should react to hard braking as i have another car fitted with abs and therefore know what its like under these conditions.

Just to have a rant about the Xantia,I cant believe how damm awkward it is to work on.Under the dashboard the other day trying to trace the wiring was a nightmare.Progress came to a halt as I couldnt really get anywhere purely down to the poor design of the dashboard.

I did find that I must have a wire that must be disconnected somewhere in the loom,but where....is anyones guess

I got the abs warning lamp to come on by bypassing this disconnected wire,but the fault still persists.
There appears to be two diodes in the circuit going by the diagrams that have been supplied to me,these only being guides and not necessarily correct.I can find one of the diodes which is bulit into the abs relay.....the other is a mystery.Maybe this has broken down causing my disconnection

Can anyone confirm something for me ,in that when you test a normal diode(not a zener or anything else) you should have very little resistance when connecting you AVO one way to it ,and very high resistance on it when reversing the AVO leads

Also if I take my car to a citroen stealer will they be able to diagnose the abs fault wth their diagnostic machine

Thanks for your replies thus far Steve

Clogzz · Unread post by **Clogzz** » 16 Feb 2006, 11:31

Confirming that a diode should measure one way only.

jeremy · Unread post by **jeremy** » 16 Feb 2006, 14:50

The diagnostic system will only read error codes. You know that you have a physical wiring fault so you know what the error code (if any is produced) will be. If any other codes are produced from the ECU they will be for a different vehicle as youe ECU is not the original one for the car.

I suppose someone could have pruned the warning light wire in the hope that an MOT Inspector or prospective purchaser would not notice the malfunctioning ABS. If it was malfunctioning it was probably a sensor which is probably still the case. HOWEVER a defective sensor will cause the light to stay ON rather than producing the problem you have.

The simple answer is to run a new wire from the ABS plug on the ECU to the warning light - but you will need a pin-out diagram for that. I think there is one (may be peugeot) on here - as someone had a strange problem in the last year.

steviewonder7 · Unread post by **steviewonder7** » 16 Feb 2006, 17:05

The thought did occur to me jeremy about the abs not working and perhaps someone trying to hide it from me.At the time of purchase of the car it didnt occur to me to ask whether the car was fitted with ABS or not.More fool me eh!!

I only asked about the possible diagnosis with a diagnostic machine at the citroen stealer because when I was tracing the wiring under the dash I thought I saw a large open socket coloured brown,thinking this was a possible diagnostic socket.Perhaps it was just a socket not used on my particular model of car.

I will try and see if I can look at a peugeot haynes manual to see if it has a wiring diagram for the abs which maybe very similar to my requirements.
Cheers Steve