James_D

No good news I'm affraid, disconnecting / replacing the battery wont make the immobiliser lose its code so that indicates another problem somewhere. When you turn the key to its 2nd turn what lights do you have? When you say it wont start does it even turn over? does it turn over plenty but not fire up? or does it sort of cough in an attempt but give in? First port of call with all these electrical faults is to go through all the fuses both in the driver side compartment (near the door under your dash) and in the engine bay (usually right hand side next to the battery) Whilst in the engine bay follow the negative earth leads and make sure they are all making good contacts, if where they meet the bodywork its all rusted remove it sand / file it down till its clean and replace it. This should give you some ideas as always more info makes it easier to diagnose, I hope its something simple / easy for you.

Late reply so I hope you havent been driving for a month with it doing this ;) This happened to me last week, the part is £60 and on a 2001 is likley to be the easier of the two to replace. All you need to do is remove the 2 Torx T20 screws that hold the plastic shroud round the steering column pull the covers appart, move the steering wheel 90 degrees left, use a Torx T15 to remove the 2 screws holding the unit in place, slide it out (its on rails) then replace. And yea its yet another "common fault" my friend at the dealership knows someone who's replaced 1 a year for the last 3 years! its basically a design fault where the mechanism that knocks it off breaks and rattles round causing it to indicate randomly though normally to one side!

Pretty much the same thing just happened to me, was working ok then mid journey the fan went onto full tilt and refused to change so whenever the car is running the blowers on full! I pulled my dash apart and tested the controls (pot sensors resistors etc) and all were ok so I gave up and got a mobile electrician out, he explained it was a common fault and pointed out a few reasons why they go (its semi common) Anyway you can get the resistor pack £70 but its much better to get the full unit £90 as for that little its worth replacing just incase the motor caused the resistor to burn out. Anyway it was £180 for me all in and from what I saw its easy to replace so you could probably do it yourself, I know I will if it go's again! and if you go to a Unipart Citroen dealer they can / will give you anything from 10%-20% off the £90 which is a bonus! tips. Blower is located in the left hand footwell behind the dash accesible by pulling the carpet out. Make sure the batt neg lead has been disconnected for 10 mins or there may still be some charge. Other than that its easy but I take no responsability for your personal safety ;) As for the Aircon not working in the reply, I have the same fault but its been like that since I got the car, not had it looked at yet but the electrician thinks it could just be low on gas as he thinks there is a sensor that stops it working if the pressures are too low, im not convinced but we'll see! James