Security/central locking – circuit operation
- Make
- Land Rover
- Model
- Range Rover P38 Electrical Troubleshooting Manual
- Year
- 1999 on
- Section
- Circuit operation › Security/central locking – circuit operation
SECURITY/CENTRAL LOCKING – CIRCUIT OPERATION
Audible/Visual Warnings
When an intrusion is detected, the Alarm Sounder (Z171) will sound and visual indicators will flash. The output from the sounder is either pulsed or a continuous tone, depending on market legislation. If the output is pulsed, then its status will be synchronised with that of the visual indicators. The lamps used for external visual indication are dependent upon market legislation, but will be either Hazards, or Side and Tail, or Dip and Tail. Two different types of Alarm Sounders are available: 1. Normal Alarm Klaxon (Alarm Sounder (Z171)) 2. Battery Backed Up Alarm Sounder (Z272) The Battery Backed Up Alarm Sounder (Z272) is an alarm sounder which contains its own internal battery. When the ignition is on, the internal battery is charged via an ignition feed. If either the connector is removed or the wires to it are cut, then the sounder will sound for 4.5 minutes. To disconnect the Battery Backed Up Alarm Sounder (Z272): Turn Ignition On (Pos. II). Turn Ignition Off. Disconnect within 17 seconds. To silence if triggered: Connect. Disarm Alarm. Turn Ignition On (Pos. II).
Alarm Triggering
The perimetric alarm will be triggered by any of the doors opening, the tailgate opening, the bonnet opening, the ignition key being inserted, the ignition being turned on, or the inertia switch being tripped. The volumetric alarm will be triggered by any movement within the passenger compartment. The alarm will be triggered a maximum of three times during any set/unset period. Any further triggers after this will be ignored.
ENGINE IMMOBILISATION FUNCTION
The engine will be immobilised whenever the alarm is armed or the alarm enters the Passive Immobilisation mode (regardless of whether or not the theft alarm is armed). There are two methods of Engine Immobilisation featured: 1. Engine Crank Disable 2. Electronic Engine Immobilisation
The electronic engine immobilisation is controlled jointly by the engine management system’s Electronic Control Module and the BeCM. If a crank signal is detected when the engine is immobilised, the “Engine Immobilised” message will be transmitted to the instrument pack, and it will not be possible to start the engine.
Engine Immobilisation (Petrol)
The BeCM mobilises the engine by transmitting an engine mobilise code to the ECM. The code is not sent when the engine is immobilised.
Engine Immobilisation (Diesel)
The electronic engine immobilisation feature fitted to the diesel engine derivatives is different to the system fitted to the petrol versions. The BeCM mobilises the engine by holding the engine mobilise output high. The output will be low when the engine is immobilised.
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