Recurring issues with keys being reset and BT not working

[Estoril]

Hi,

I've already posted about this issue I'm having before, but I'm really hoping to find someone who can give me some pointers on where to start looking.

Every couple of days the car forgets/resets the keys it has in memory, no longer allowing me to use the remote buttons on the keyfobs. When this happens I open the car with the key manually and the alarm always goes off until I put the key in the ignition. It always starts fine, never had an issue there.

At the same time, my Bluetooth connection sometimes just totally falls away. It disconnects and the Bluetooth channel can no longer be found. It shows up again (and auto-connects) after like 10-15 seconds, but then it stops again always within a minute.

It feels like the issues are related, because they started happening somewhat around the same timeline. Also they often happen together, but not always. I thougth maybe the aftermarket Bluetooth adapter was causing some issues on the frequency of the EWS module, causing it to reset or get confused. But I drove around without the Bluetooth adapter for a while and the key-resetting issue did not stop. So this did not solve the issue. Not sure what else I can do to get some more information on the issue. Reading out the car's fault codes show zero codes except something on a sensor in the exhaust system, that's it.

The aftermarket Bluetooth adapter was installen by the previous owner, it's a "BlueMusic" adapter which replaces the CD player. The car is a 2002 4.6is. When I say it resets keys, I mean it resets *both* remotes that I have.

I know the key info is stored in the EWS module, so I figured maybe it has some kind of fault. I could ask my indy mechanic to send it to their software guru so he can test it out, but it's quite pricy and I'm not really sure if the issue even lies there. I'm willing to put some money into the issue if needed, but I'd like to have an idea of where the issue is coming from before I start throwing money at it.

Link to the Bluetooth adapter: https://www.amazon.nl/BlueMusic-Blue...language=en_GB