Im using Ulysee 2.0EL Petrol. This morning when I wnat to enter the pin
number on my immobiliser, the red light keep flashing, and i just could not
enter it. Help me, what's the problem?. (there was not any problem since I
last used lasty night,battery ok).

Could be a problem with broken wires on the flip out panel.
We had one and the panel went mad. Turned iout the connecting wires had all fractured and broken.
Managed to repair it all my self.

sounds like the wire have broken at the rear. If you manage to get the wires back into the connecter, when the vehicle is running disconnect the unit and you will never need to entry the code again.

Alternatively Peugeot do a repair loom (meant for the 405) which can be fitted by a decent electrical technician.

Thanks. If i try repairing the "broken wire", would the MCU intrepret it as attempt to bypass the immobilizer thus activating anti-theft measures, screwing the whole thing? What are the precautionary measaures or required procedures, if any?

thanks. is it safe just snipping the wire and reconnect?
really desperate.

Just disconnect the battery and you should be fine.

I think I did all mine live when I did it. As long as you are careful not to short anything out by working on only 1 wire at a time it should be fine.
With the batetry off your sure to be ok.
Note I had to re-do all mine as a few were broken but lots were close to breaking so cut them all back a bit and re-connected.
Doesn't help that they are all the same colour from what I remember.

I've been busy last two days, finally last night I carefully examined the wires and found three severed wires, and I dont know which is which and tried my fisrt guess of the combinations, it was wrong. After two tries, I finally found the right combination and the red light goes steady and after enterting the code, the engine fires!. Thats's great men! I really thanks to both of you for giving me the tips and more importantly the courage!. Thanks again.

p/s I could not remove the connector even after pulling out hard. So I leave it like that. Continue entering the code....

I also found that the plastic lugs that hold the keypad in place and allows it to swivel kept breaking. A short length of metal from an old drying rack made it a solid as rock.