Citroen XM Forum

Hi Folks,
I am a past XM owner, trying to help a friend, without IT access. The Situation as now.
My friend owns an "R Reg" Xantia petrol 16valve,everything working okay until it dropped a cambelt.Vehicle off road for sometime with battery removed. Replacement engine found for vehicle, but as engine is newer,wiring harness is different. Old harness removed & fitted to replacement engine. Engine fitted. First off Code pad would not accept last known code which worked until engine failed. 2 red lights. 0000c entered & new code, now getting 1 Green & 1 Red. New batteries in 2 button key plip(fob)& tried/checked re-synchronize key. Still showing 1 Red light. On turning key the fuel pump can be heard, the engine will crank, but will not start. Does the Red light (immobiliser)knock out the ignition at the ECU ? Has the ECU developed a memory loss, because it has not been used for sometime ? If ignition is left switched on for sometime will it reboot the ECU ? Now checking for poor electrical contacts/earths ! Plug will be removed to check for fuel & spark. Suspect RED LIGHT is the problem, but what has changed ?
ANYONE GOT ANY THOUGHTS THAT MAY HELP PLEASE. JIM.

Posted on CCC also.

Hi Jim

May need to know a lot more about the build date of both the old engine and the new engine.
My experience is XM's but suspect that Xantias went through similar immobiliser changes.
From 1995 to 1998 Citroen made some 4 or so changes to the immobiliser system.
There is very little compatibility between the different systems.
That said you seem to have maintained fully the original wiring, keypad and ECU.
As I understand it with XM's from late "P" reg there was a rather difficult immobiliser version where the ECU keeps two seperate user selectable 4 digit codes. One is the main users code and the other the garage code.
It is possible to buy a car and be given just the garage code.
Because it is a user selected unique number most people assume that it is the main code.
Unfortunately this garage code is lost from the ECU on battery disconnection.
In this state the ECU reverts to the previous main code as the only way to release the immobiliser.
If you have no record of the main code then you have just 3 chances to guess it before the ECU locks up permanently with the red and green lights on.
Not aware of any easy fix for this.

John

Hi John,
Thanks for your reply & comments to my posting. You are the only one from 2 Citroen web sites. Perhaps everybody else is as baffled as we are !
"XM crew" normally find comments on most things. Although I am a past XM owner, I still visit the site often & enjoy.
ZANT is still a non runner !
Looking at things rationally, the only thing to have changed is the ENGINE & nothing else. Harness from old engine fitted to replacement engine. Everything "In Board" was working prior to cambelt failure. My friend is a mechanic & the ZANT is a "Fix it as a Project" thing. He is old school & trained by Lucas Aerospace & very thorough, but the "French Electrics" have him thinking on this one. As he is trying to earn a living, the ZANT gets looked at as and when. His next step is to find which is missing, Spark, Fuel or Both as the engine cranks, but will not start ! I am of the opinion it is connections somewhere that are not making contact to fire "A RELAY". The vehicle has been garaged for sometime now. Could well be the ECU has "locked out". The only "chips" we knew you could eat. The new ones upset your line of thought. Years ago most things were "FIXABLE", using logic ! ! Why are things, made to simplify, now so complicated ? ? ?
And we are going to merge with the French ! ! GOD , what doe's the future hold in store ? ? ?
Once again, thank for the reply, keep an open mind & more thoughts welcome. Will keep you posted.
Best Regards JIM.

Hi Jim.

Just to add a bit of extra confusion -- which may be quite irrelevant --- we have an R reg Xant in the household which has no keypad at all, but key fob recognition. Is it possible your replacement kit is designed for this alternative form of security ? After a fairly long lay up, I had all sorts of grief when recommissioning my XM trying to get the code pad to play. I was lucky in having a complete spare 'bitzer' to have a go at, but even with the benefit of spare, known code ECU and spare keypad, it still seemed temperamental. One mistake I found I had made was in mis-connecting a couple of the multiplugs somewhere near the ECU box. Because nearly all the connectors on the XM are colour and profile coded, I made the mistake of assuming they all were --- not so -- these pair of brown ones happily fitted each other's socket. I certainly don't think the keypads like long periods of no use -- wonder if the damp gets at them ? Good luck with it.

Mike.