^^ there easlly changed to resync the fob to the car you need to turn the ignition on and press the lock key it will lock then unlock to show pairing
the fobs are a common fault with ether the batter tray of the buttons failing at some point both battery tray and buttons are repairable with a little patience and a soldering iron
the other commonplace fault is the alarm siren unit
the internal rechargeable batteries fail and leak acid inside the case causing permanent damage to the units pcb its cheaper to buy a working replacement and fit new batteries.
siren faults are normally indicated by random middle of the night alarm going off getting more frequent as the charge in the batteries get lower#
heres a 2nd hand unit i bought for mine and fitted new batterys not easy but for £24 fixed it was cheaper than £76 for a new power sounder 🙂
