The Land Rover fault code (often abbreviated as B1D1787) typically indicates a failure of the internal battery within the Alarm Siren Module . This specific sub-code suffix (-87) denotes a "missing message" or communication failure, usually triggered when the siren's backup battery is dead or the unit has an internal hardware fault. Symptoms "Alarm System Service Required" message on the dashboard. Random alarm triggers without a clear cause.
Always verify part number compatibility with your vehicle’s VIN and prefer OEM parts when maintaining system reliability. Keep diagnostic logs and part receipts in case warranty or return becomes necessary.
: Moisture intrusion in the wheel arch area can corrode the pins on the sounder’s electrical plug.
A "Service Theft Alarm" or similar message on the instrument cluster.
