hi, had a customer today call me out

remote central locking stopped working,
he has spare remote key which has never been used - customer had car from new - also not working.

1. i tried frequency output both remotes - fine
2. i tried diagnostics on bcm unit - no fault codes
3. i tried battery disconnect and pulled all the fuses in the interior box where obd socket is
4. central locking button functions inside the car fine


what coud this be? it was all of a sudden, customer came out from shop and remote didnt work.