removed battery now the immobilizer needs resetting - how?

[ihatecars]

The battery on my 1995 Xantia 1.8 petrol was dead so I removed it for a few days while the new one was delivered. I now fit the new battery and the engine started perfectly so I switch it off.
I return a few minutes later to go to the supermarket and now the engine won't start, it turns at speed but no ignition. I'm told the immobilizer has kicked in. I gather the immobilizer now needs resetting, how do I do that?

I noticed, when I connected the new battery the alarm didn't sound (which it did previoulsy). The door key doesn't operate the central locking (but does mechanically), the internal clock is not working. My local garage man tells me there is some procedure needed to reset the immobilizer, does any one know what to do?

Many thanks

[RichardW]

A 95 Xantia will only have the key pad immoiliser - there is no re-set procedure, enter the code and the light goes green and it will (should!) start. Alarm function is independent - siren may have been silenced, but then the headlights should still have flashed. It may be co-incidence, and something else has gone wrong - cambelt OK? My Dad had a crank sensor spontaneously die on a 1.8 Xantia.

[citronut]

it might be worth disconectting the negative terminal off the battery and leave it off for a couple if minuites, then reconect it,
if the head lamps keep flashing you need to press the volumatric alarm button within a couple of seconds after turning the ignition on,

regards malcolm

[ihatecars]

Thanks for the advice, it helps. I'm almost there now. I found the immobilser number, put it in, cranked the engine, 3rd open throttle (usually not necessary) and it started! Puzzle is, the green LED was lit before too - dunno.

As RichardW says, I've looked at the circuit diagram, the clock and central locking sensor are on the same 2A fuse (along with the radio/CD). That fuse was blown, seems like all the reconnecting and disconnecting the battery caused the radio/CD to take lumps of current.

Alas all I have now is, the engine won't tick over, foot off throttle the engine slows to stall. Otherwise the engine is fine. I had this same problem when I first bought the car, the dealer cleaned out a "valve" (not cylinder), said it was clogged with engine goo.
Just been reading previous posts: yes this was it "idle stepper motor" - where is it? What it look like? I guess being a stepper motor there will be some wires to it.

I've done a photo, which is the idle stepper on my engine pls.

[citronut]

i dont remember seeing one of those like pointed to in your picy on a XANT, as that is cold start auxiluary air supply valve i think,

the idle stepper motor is usualy a smaller black device that is conected to the throtle body,
like the one in the ebay link below

http://tinyurl.com/7kjhuwr" onclick="window.open(this.href);return false;

you might find it was upset whilst the battery was disconted, because if you disconect a stepper motor on reconecting they have to be re/set by turnning the ignition on and off two or three times, before startting the engine,

regards malcolm

[citroenxm]

Yes thats the idle valve, its the same on Citroen XMs but its attached to the battery tray on the 2.oi Turbos...

That will need clearing out, they do get crap in them, specially on short journeys, which in a petrol is a big killer over time...

Paul

[xmexclusive]

I might be able to suggest why the immobiliser light went green when the new battery was first fitted.
Last month I was investigating a Citroen XM ECU to find and read the data storage chip.
I got as far as finding where and how the Immo code stored.
To do this I had to keep changing the Immo code.
Each change meant powering down the ECU to remove and read the memory chip.
On reinstalling the ECU normally I got a red light and the ECU happily accepted the new Immo code.
About one time in four on average though I got the green light straight up.
Engine would restart without needing code, try it again and the ECU might go red, clear itself or just lock up.
Only way out of lock up was to disconnect the ECU and power it back up again.
It seems to me that an ECU microprocessor can occasionally fail to boot up correctly on power up.
In normal use of course the ECU remains powered ignition on or off so never gets powered down.

John

[ihatecars]

RESULT!!
I dismantled that unit, turns out to be a captive 3 wire DC motor, I just cleaned it all (no fluids), commutator, brushes, contacts etc. There are 3 connections that measure near enough 20-20-40 ohms. Reassembled, install back in car, it starts so quick and tickover is sweet as a nut, great job.

BTW: the item is Bosch 0-280-140537