-02 Xsara HDI 2.0 - Key not recognized after battery disconnect / reconnect

[manabreak]

I checked for some faulty wires in the rear left door and for that, I disconnected the battery. After I was done, I reconnected the battery, but now the key is not recognized at all. The engine does turn when I try to start, but it won't start. Also the central locking system won't lock or unlock by pressing the buttons on the key. Similarly, the spare key (no buttons on that one) doesn't start the engine.

There's the little yellow key sign on and the small red LED on the hazard blinker button is also on. I've tried turning the ignition on and pressing the buttons on the key for various times (10s, 30s, 1 minute...) to no avail. I tried both buttons simultaenously and individually. I've also done the "three minute rule" reset where I turned everything off, took the key out of the barrel, opened the driver's window and the bonnet and waited about five minutes before disconnecting the battery. After a while I reconnected it and heard a "bong" sound come from the cabin. I waited a moment, turned the lights on through the window, waited some more, put the key into the barrel, turned ignition on... And the lights are on. Again, I tried the button pressing thingy but it didn't help.

What I've read from other posts is that the "bong" sound should happen when the lights are turned on (or other "soft" boot is done), but in my case, the sound happens almost instantly after reconnecting the battery.

Also, I called to a friendly car repair shop where they said that it could be the fuel cut-off switch and told me to locate it and press it. I searched for it for a looong time, but couldn't find it. The manual says it should be on either of the suspension mounts, but nope, nothing there. I tried tracing every cord and hose I could find, but no cut-off switch.

Is there anything I can do? Or do I just have to call the shop and tow the car there?

[RichardW]

Welcome! It sounds like the BSI has forgotten some settings - possibly because you were a bit hasty in taking the battery off before it had gone to sleep.... Anyway, it will need to be put on a Lexia Diagnostic computer to re-program the keys (and possibly the whole BSI). You may well be best in buying the Lexia kit and doing it yourself, as otherwise it will need to go to a Citroen dealer, who will no doubt charge the earth!

[wheeler]

You will also need the 4 digit imobiliser security code to reprogram the keys.

[lexi]

You will also need the 4 digit imobiliser security code to reprogram the keys.

Where is that obtained from?

[Hell Razor5543]

You can get that from Citroen, but (depending on the dealership) you might need to take proof of ownership with you. They will probably charge a fee, about £10.

[wheeler]

The code should have been supplied with the car when new in the handbook pack, it would have been on a grey plastic credit card style card with a code on it.