BCU won't wake up by remote

[nimrod10h]

Hi have a pug 307 1.6 hdi 07
Put battery back on and alarm kept going off. Remote only works after inserting key into door and unlocking .
Remote works fine after this car locks unlocks on the fob
Once the BCU goes to sleep it won't wake .up. problem started after I used an Audi
Key fob to unlock by pressing remote .
It did go through a phase when it went back to normal but stopped again .
Do I need a BCU ?

[GiveMeABreak]

If you remove or disconnect the battery you need to properly reinitialise the fobs or you'll have issues with the immobiliser / locking.

BSI Reset / Battery Disconnect / Reconnect Procedure