This problem seems to happen more and more, and there is like NO info anywhere.

The old Peugeot/citroen 1.9 idi diesel (aka xud etc) is an excellent engine and a lot of people like it. Its popular in the motorhome community And also in the veg oil community.

Unfortunately it has THE stupidest immo ever. Do you know the system im talking about?
The immo system has a antenna around the barrel (or sometimes a keypad!) and a small immo box. The second part of the immo is under an armored tamper-proof shield on the fuel pump. Its fixed on with single-use bolts so you cannot unscrew them.

So these engines are now 25+ years old (?) and of course keys get lost, etc.

The traditional way to deal with this is to physically cut off the tamper-proof steel cover, or various methods to unscrew the tamper-proof bolts etc. then you can remove the immo totally and just feed 12v to the fuel valve and everything is ok.
BUT thats a huge pain in the ass. Its ok if the pump is not on the engine, but in real life, when the pump is on the engine, the engine is in a big Ducato motor-home, the Ducato is stuck somehere and cannot move because of immo problem, and its usually raining? its very time-consuming and awkward to do.

I was thinking, with the millions of XUD engines out there (they were very popular for a long time!)'there MUST be a software solution?

Does anybody know how this system works?
If i went to a Citroen dealer in 1998 and said hi i have this car but i lost the key, how did they program a new key?
There seems to be no obd at all, how did they even access the system?
The immo box has a eeprom, but the usual software for making xponder dump from immo dumps and things doesnt recognoze the dump.

Of course the ultimate solution would be a immo-off.

How did people deal with this back in the 1990s and 2000s?

If you have one of these cars and lost the keys, what do you do (apart from cut off the immo cover?)

NOBODY seems to know!

Maybe somebody here knows.

I tried to look for info everywhere and nobody knows.

There must be somebody somewhere who worked on these systems back in the day.

So far all my attempts to find this info failed.

I really can't see the sense in having the hassle of the immo box and wiring etc.

I have done loads in situ, usually I can get a 30-35mm hole saw in there and drill exactly where the solenoid is. The drill bit usually destroys the original stop solenoid but that doesn't matter, just replace it with a standard lucas solenoid and provide a 12v feed. I even know someone who uses a plasma cutter. If I can't get a hole saw in there I usually use a small angle drill and drill loads of holes then hammer a section out. I've never been beat yet.

By the time you mess about bypassing the immo you'd have the old solenoid off and new one on. I think that's the reason nobody has gone through the effort of reverse engineering it. Even with the immo bypassed you have a lot of stuff that can go wrong and when the car refuses to start due to another immo problem you will wish you just swapped the stop solenoids on the pump.

Hello Juan.
You have mention that some of those cars had keypad. I did have keypad immo in my old Citroen XM but with different engine. The way to disable it, was set the PIN to "0000" and then disconnect the keypad while engine was running. Next time when you tried to turn on the engine it did not ask for PIN.