C5 2.2 HDi Immobiliser ECU - Where is it?

[xantom]

Hello folks,
This is a follow on from a request I submitted in a slightly irrelevant earlier post when I'd had a brain fuse and couldn't work out how to create a new post.
The immobiliser on my C5 2.2 HDi Mk1 has failed on me. Great efforts by an impressively knowledgeable Green Flag engineer failed to rekindle it so it's static on my drive again. I've got a Lexia and soon will have a laptop that works to load it onto. In the meantime though I'd like to remove and replace the immobiliser ECU as I've read that this sometimes revitalises it (I can't try a proper BSI reset because she's gone into economy mode and I can't get the window down).
Can anyone tell me where the Immobiliser ECU is located? Any other pearls of wisdom about recovering failed immobiliser systems will be gratefully received too.
Thanks,
Tom

[Peter.N.]

I think that the immobiliser system is part of the BSI. I had problems with the one on my 406 due to water ingress and after a lot of work ended up scrapping it. Hopefully the outcome of yours won't be as drastic and someone will come up with the answer, if they do I wish they had done it sooner

Peter

[teuski]

The immobiliser system consists of the engine ECU, BSI and the chips in your keys and they all need to match. There is no separate immobiliser ECU.

You need to get all those from same car or have your engine ecu flashed to remove the immobiliser.

Or go to an official citroen garage and have them do their thing, which probably is pretty expensive...

[GiveMeABreak]

If you want to try the BSI reset and it's in economy mode - you'll have to bodge the fiirst attempt in order to get the window down:
Open the bonnet, disconnect the battery negative for a minute - reconnect, turn ignition to accessories and open window. Then you can try the BSI reset again properly - but allow some minutes for the car to 'sleep' and again on 'wakening'.

I'd also suggest taking the opportunity to check your battery - when was it last changed? - Might be worth giving it a charge regardless before trying the second BSI reset.

[wheeler]

Why would you need the window down to do a BSI reset ??

[GiveMeABreak]

Normally to switch on sidelights and perform the key fob part of the procedure without opening the doors and waking the network.

[wheeler]

Normally to switch on sidelights and perform the key fob part of the procedure without opening the doors and waking the network.

You can just leave the door open during the procedure, opening or closing the door wakes the network. If you leave the door open & Wait 3 minutes the BSI will go back to sleep as long as you don't close the door again. Its the changing of the state of the door that wakes up the BSI not the position that the door is in. I resync the keyfobs after waking the network anyway. Trying to do the reset on a C8 could get quite awkward with the door closed as the battery is in the floor.
The other alternative if you would prefer the door to be closed is to just close the catch over with a screwdriver to trick the BSI into thinking the door is closed.
I suppose everyone has their own method reset procedure that works best for them. Mines is:
Have the battery accessible (either bonnet, boot or door open depending on model).
Allow the BSI to go to sleep by waiting at least 3 minutes without opening or closing doors, pressing the keyfob buttons (or any buttons for that matter).
Disconnect both battery leads then connect a 12v bulb across the 2 battery leads for a few seconds to discharge any residual current.
Reconnect the battery after a few minutes then wait at least 3 minutes before doing anything else (pressing buttons, opening or closing doors etc)
I then lock the drivers door with the keyblade (closing the door first if it was open), wait a few seconds then unlock again with the keyblade, this will wake the BSI anyway as will turning the ignition on.
I then get in the car & close the door, switch the ignition on and rapidly press the keyfob buttons alternating between the lock & unlock buttons for 10 seconds, remove the key, insert & do the same with any other keyfobs, after the last kefob is done wait one minute without pressing the buttons or opening the door (this method gives me the best success resyncing the fobs for me.
lock then unlock with each remote, open then close the door then start car.

[GiveMeABreak]

I appreciate some of us have 'modified' the procedure slightly Wheeler, (including me for my use), I just didn't want to list yet another version that detracts too much from the one that the OP is obviously looking at. Just trying to keep it simple! :-

[wheeler]

I have never actually read the version in the link in the forum till a couple of minutes ago hence wondering why the OP was thinking the window needs to be down, don't really see the need for the sidelights bit & have never done this, The wait times between each step are a bit excessive especially the half hour before reconnecting the battery. I do appreciate however that it may be someone's first time doing this & will want to take their time with each step which there is nothing wrong with of course.
I do agree that just sticking with the one version could avoid confusion, can be a lot to take in if its something your not used to.

[GiveMeABreak]

I have never actually read the version in the link in the forum till a couple of minutes ago hence wondering why the OP was thinking the window needs to be down, don't really see the need for the sidelights bit & have never done this, The wait times between each step are a bit excessive especially the half hour before reconnecting the battery. I do appreciate however that it may be someone's first time doing this & will want to take their time with each step which there is nothing wrong with of course.
I do agree that just sticking with the one version could avoid confusion, can be a lot to take in if its something your not used to.

Some procedures say wait a few seconds (!) for the network to sleep which is ridiculous. I believe that when you hear the 'click' from inside the car, that is indicative of the 'sleep' mode going active.

[wheeler]

I believe that when you hear the 'click' from inside the car, that is indicative of the 'sleep' mode going active.

Correct about the click, takes around 3 minutes.