BODY CONTROL UNIT (Description): DESCRIPTION AND OPERATION (page 13 of 18)

BODY CONTROL UNIT

DESCRIPTION AND OPERATION 86-3-13

Anti-theft system
The BCU controls the logical switching operations for enabling and activating the anti-theft system. Features include:

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Perimetric protection – monitors the condition of doors and hinged panels.

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Volumetric protection – monitors the vehicle's interior space.

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Remote locking, superlocking and unlocking functions.

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Engine immobilisation and remobilisation.

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Advanced mislock detection and automatic compensation.

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EKA code functions.

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Customer configuration options.

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Market configuration options.

Immobilisation
The immobilisation system comprises the following components:

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RF receiver.

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RF transmitter/ transponder.

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Transponder coil.

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BCU.

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Door switches, door lock switches and bonnet switch.

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IDM.

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ECM.

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Starter solenoid relay.

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Status LED.

Alarm system
The alarm system comprises the following components:

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RF receiver.

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RF transmitter.

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BCU.

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IDM.

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Door switches, door lock switches and bonnet switch.

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Battery backed-up sounder (BBUS).

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Status LED.

On non NAS vehicles, power supply for the alarm sounder and the battery BBUS is provided through two relays in the 
passenger compartment fuse box. Each of the coils of the alarm relays are directly connected to the IDM which 
controls their operation under the direction of BCU signals received via the serial data bus.

On NAS vehicles, an audible warning is provided through operation of the vehicle horns. The BCU provides an earth 
path for the coil of the horn relay to initiate vehicle horn operation.
 

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 ALARM SYSTEM AND HORN, DESCRIPTION AND OPERATION, Description.

Acclimatisation locking

Disabled

The vehicle cannot be locked if the ignition is on.

Enabled

The vehicle can be locked if the ignition is on and the engine is 
running.

Alarm tamper

Disabled

The security system LED does not flash when the security system has 
been tampered with.

Enabled

The security system LED flashes when the security system has been 
tampered with.

Engine immobilised

LED off

The security system LED does not flash when the engine is 
immobilised.

LED flash

The security system LED flashes when the engine is immobilised.

Low battery warning

Disabled

The security system LED does not flash when the remote transmitter 
battery is low.

Enabled

The security system LED flashes when the remote transmitter battery 
is low.

Emergency Key Access 
(EKA)

Disabled

EKA is disabled.

Enabled

EKA is enabled and the door locks operate electrically.

No unlock

EKA is enabled, but the door locks do not operate electrically.

Function

Option

Details