Leaderboard

If you look in the car handbook it should say how to replace the battery in the fob. This should include an initialisation procedure. I suspect you might need to do this on both fobs at the same time or open the car with one fob and initialise the other and see if they both work together without the rigmarole.

Admin only comes on the forum maybe once a year or unless there are any problems so I would just wait and see what happens.

I have no idea about the modulation. If it is just the case that needs replacing and the internal electrics are still working then I would only buy a case and put the existing electrics and key blade into the replacement case - I have done this a few times on Citroen cars. If the remote just needs a new battery then the car handbook says how to replace it. Something to be aware of, a replacement will likely not work with the car immobiliser, the immobiliser chip will need to be removed from the old remote and put in the new one but if it is built into the circuit board I do not know how y

If it is a dash board mount then it is likely to be an after market one such as a Tom Tom or Garmin. You could remove the mount and take it to somewhere like Halfords and see if it can be identified to see which sat nav fits. The other option is to just buy one that you like best at a price you are happy to pay. We have used a couple of Garmins on cars without a built in sat nav and they worked well enough with a mount that clipped them to the central air vents. The power lead was simply plugged into the nearby 12 volt socket. When not being used they were removed from the car.

Welcome to the forum. I can not help other than ask a Citroen dealer to listen to the engine to see what they think. Out of interest, which engine do you have ?