1999 LAND ROVER DISCOVERY warning

BODY CONTROL UNIT
DESCRIPTION AND OPERATION 86-3-1
BODY CONTROL UNIT DESCRIPTION AND OPERAT ION
Description
General
The Body Control Unit (BCU) is located behind the passenger glovebox and is connected to the main harness by four
connectors on its bottom edge and an additional connector located on the side of the BCU casing. Mounting the BCU
behind the fascia makes it reasonably inaccessible for intruders to disable the anti-theft system.
The BCU uses solid-state microprocessor control to perform logical operations and timing functions for a variety of
the vehicle's electrically operated systems, these include:
lDoor locking.
lAnti-theft alarm and immobilisation system.
lExterior lighting including direction indicators and hazard warning lamps.
lCourtesy lighting.
lWipers and washers.
lElectric windows and sunroof.
lHeated windows.
The BCU also communicates with several other electronically controlled systems such as the EAT ECU and SLABS
ECU and also has a datalink between the Intelligent Driver Module (IDM) and the instrument pack. The datalink is a
low speed bus capable of transmitting and receiving messages at a data rate of 10,400 bits per second. Additional
inputs and outputs to peripheral devices are included which are necessary for determining vehicle status for particular
logical operations e.g. crank, ignition key inserted, fuel flap enable etc.
The BCU receives its power supply from the engine compartment fuse box, and is protected by a 10 A fuse.
The BCU communicates with the IDM to provide the control signals to perform power switching operations in
conjunction with dedicated relays.
IDM
The IDM is integrated into the passenger compartment fuse box, which is mounted behind the fascia below the
steering column. There are no harnesses between the fuse box and the IDM. The IDM performs the power switching
operations for several of the vehicle's electrical systems.
The IDM communicates with the BCU and the instrument pack via a serial interface. If the BCU or the IDM is replaced,
the communications link between the two units has to be re-established. This can be done either by switching on the
ignition and leaving it on for five minutes, or by using TestBook. The vehicle immobilisation will remain active until the
communications link between the BCU and IDM has been re-established.
Transit mode
To prevent excessive battery drain during transit to overseas markets, the vehicle is placed in a transit mode. The
following functions are disabled when the vehicle is in transit mode:
lVolumetric sensors.
lPassive immobilisation.
lImmobilisation of the vehicle by use of door lock.
lIgnition key interlock.
lElectric seat enable time-out with driver's door open.

BODY CONTROL UNIT
DESCRIPTION AND OPERATION 86-3-3
BCU outputs
The BCU processes the input signals it receives and uses the information to determine the control outputs that need
to be established for any given set of conditions. The BCU provides controlled outputs for the following systems:
lInterior courtesy lamps.
lFuel flap release actuator.
lAnti-theft status LED.
lEngine Control Module.
lDoor lock actuators.
lDirection indicators and hazard warning lamps.
lHeadlamps.
lAlarm sounder.
lVehicle horns.
lBattery backed sounder.
lStarter relay.
lPassive re-mobilisation exciter coil.
Simultaneous switching of outputs in different units is limited by the bus transfer time, but the skew is no longer than
100 ms for either the BCU or the IDM. When the processor is reset, all outputs are switched off until the inputs have
been read for the first time to check current condition.
BCU to harness connectors
1Connector C0661
2Connector C0662
3Connector C06634Connector C0660
5Connector C0664
The pinout details for the BCU connectors are defined below:

BODY CONTROL UNIT
86-3-4 DESCRIPTION AND OPERATION
C0660 connector pin details
Pin No. Description Input/Output
1 Ignition power supply Input
2 Right front window - down Input
3 Auxiliary power supply Input
4 Passenger or rear door open Input
5 Driver's door key lock Input
6 RH indicator selected Input
7 Front fog lamps selected Input
8 Gear position feedback 'R' Output
9 Gear position feedback 'P' Output
10 SLS too high (audible warning) Input
11 Earth -
12 Vehicle raise/lower request Output
13 Battery power supply Input
14 Heated front screen selected Input
15 Bonnet open Input
16 CDL doors lock Input
17 Driver's door open Input
18 Left front window up Input
19 Right front window up Input
20 Rear washer pump Input
21 Front intermittent wiper switch Input
22 Gear position feedback '1' Output
23 Gear position feedback '2' Output
24 Gear position feedback '3' Output
25 Gear position feedback 'D' Output
26 Gear position feedback 'N' Output

BODY CONTROL UNIT
DESCRIPTION AND OPERATION 86-3-7
C0663 connector pin details
Pin No. Description Input/Output
1 Crank selected Input
2 LH direction indicator selected Input
3 Driver/Passenger seat enable Output
4 Front fog lamps Output
5 Heated rear screen selected Input
6 Ultrasonic input Input
7 Gear position switch (Z contacts) Input
8 Ultrasonic power supply Output
9 Courtesy lamps Output
10 Feed to gear position switch (W, X, Y, Z contacts) Output
11 Park/Neutral selected Input
12 Hazard warning lamps Input

BODY CONTROL UNIT
DESCRIPTION AND OPERATION 86-3-9
IDM outputs
The IDM receives the following signals from the BCU using the serial datalink to provide power outputs:
Description Signal type System
Unlock all doors enable Digital Locking/ Unlocking/ Alarm
Lock passenger and rear doors enable Digital Locking/ Unlocking/ Alarm
Superlock all doors enable Digital Locking/ Unlocking/ Alarm
Lock driver's door Digital Locking/ Unlocking/ Alarm
Rear fog lamps enable Digital Exterior lighting
Daylight running lamps enable Digital Exterior lighting
LH direction indicators enable Digital Direction indicators/ Hazard warning/ Alarm
RH direction indicators enable Digital Direction indicators/ Hazard warning/ Alarm
Gear position indicator illumination Digital Illumination
Headlamp main beam indicator disable Digital Illumination
Front wiper enable Digital Wipers and washers
Rear wiper enable Digital Wipers and washers
Rear window enable Digital Power windows
Shift lever solenoid enable Digital Automatic gearbox
Transfer box solenoid enable/ Alarm sounder
relayDigital Gearbox
Heated rear window enable Digital Heated screens

BODY CONTROL UNIT
DESCRIPTION AND OPERATION 86-3-11
Programmable options
The BCU can be programmed with a number of options to satisfy specific market requirements and customer
preferences. The options can be set using TestBook.
Function Option Details
Transmission Manual The vehicle is fitted with manual transmission.
Automatic The vehicle is fitted with automatic transmission.
Front fog lamps None The vehicle is not fitted with front fog lamps.
Main The front fog lamps will operate if the headlamps are on main beam.
No main The front fog lamps will not operate if the headlamps are on main
beam.
Interlocks None The vehicle is not fitted with key, shift or transfer box interlocks.
Shift The vehicle is fitted with key, shift and transfer box interlocks.
No transfer The vehicle is fitted with key and shift interlocks, but not a transfer box
interlock.
Daylight running lamps None The vehicle is not fitted with daylight running lamps.
No main The daylight running lamps are on if the headlamp main beams are off.
No heads The daylight running lights are on with headlamp main and dipped
beams off and the gearbox not in Park.
Programmed wash/ wipe Normal The front wipers operate if the front wash is operated.
No wipe The front wipers do not operate if the front wash is operated.
Key-in warning Disabled The ignition key in audible warning is disabled.
Enabled The ignition key in audible warning is generated if the ignition key is in
and the driver's door is open.
Electric front seats None The vehicle is not fitted with electric front seats.
Normal Electric seat adjustment is available for 45 seconds after the driver's
door opens or if the ignition is on.
Ignition II Electric seat adjustment is available if the ignition is on.
Electric front windows Driver cancel The front windows will be disabled 44 seconds after the driver's door
is opened.
All cancel The front windows will be disabled 44 seconds after any door is
opened.
No cancel The front windows will be disabled when the ignition is turned off.
Heated front screen Fitted The vehicle is fitted with heated front screens.
None The vehicle is not fitted with heated front screens.
Rear windows and sunroof Driver cancel The rear windows and sunroof will be disabled 44 seconds after the
driver's door is opened.
All cancel The rear windows and sunroof will be disabled 44 seconds after any
door is opened.
No cancel The rear windows and sunroof will be disabled when the ignition
switch is turned off.
Gear position indicator
illuminationAlways The automatic gearbox selector illumination is on when the ignition is
on.
Sidelights The automatic gearbox selector illumination is on when the ignition is
on and the sidelights are off.
Hill descent control None The vehicle is not fitted with hill descent control.
Fitted The vehicle is fitted with hill descent control.
Courtesy headlamps Disabled The vehicle is not fitted with courtesy headlamps.
Enabled The vehicle is fitted with courtesy headlamps.
Odometer error warning Disabled The odometer will not flash if there is an odometer error.
Enabled The odometer will flash if there is an odometer error.

BODY CONTROL UNIT
86-3-12 DESCRIPTION AND OPERATION
Seatbelt warning lamp Timed The warning lamp is on for 6 seconds after the ignition is turned on.
Buckle The warning lamp is on for 6 seconds after ignition is turned on or until
the buckle is fastened.
Ignition II If the buckle is unfastened when the ignition is turned on then the
warning lamp comes on for 6 seconds.
Disable The warning lamp is not used.
Seatbelt audible warning Timed The audible warning is on for 6 seconds after the ignition is turned on.
Buckle The audible warning is on for 6 seconds after the ignition is turned on
or until the buckle is fastened.
Ignition II If the buckle is unfastened when the ignition is turned on then the
audible warning is on for 6 seconds.
Disable The audible warning is not used.
Bulb failure warning Disabled Direction indicator bulb failure detection is disabled.
Enabled Direction indicator bulb failure detection is enabled.
Superlocking None Superlocking is not available.
Double The vehicle will superlock on a double press of the remote transmitter
or double key turn.
Single The vehicle will superlock on a single press of the remote transmitter
or a single key turn.
No key The vehicle will superlock on a single press of the remote transmitter
but not with the key.
Door unlocking Not SPE The SPE (Single Point Entry) function is not used. All doors unlock on
a remote transmitter press.
SPE Only the driver's door unlocks on the first remote transmitter press, all
other doors on the second press.
Alarm disarming Always Operation of the key in the driver's door always disarms the vehicle.
Key only Operation of the key in the driver's door only disarms the vehicle if it
was locked with the key.
Key never The security system is not disarmed by the key (except for EKA).
Inertia switch No hazards Operation of the inertia switch does not operate the hazard warning
lamps.
Hazards Operation of the inertia switch operates the hazard warning lamps.
Speed locking Disabled Speed related locking is disabled.
Enabled Speed related locking is enabled. The door locks are disabled when
the vehicle is moving.
Volumetric sensing Disabled Volumetric sensing is disabled.
Enabled Volumetric sensing is enabled.
Alarm Disabled The vehicle is not fitted with a security system.
Enabled The vehicle is fitted with a security system.
Passive immobilisation Disabled Passive immobilisation is disabled.
Enabled Passive immobilisation is enabled.
Hazard warning lamps Disabled The hazard warning lamps do not flash on security system arm,
disarm or trigger.
Enabled The hazard warning lamps flash on security system trigger only.
All The hazards flash on security system arm, disarm and trigger.
Mislocking audible
warningDisabled Mislock audible warnings are disabled.
Enabled Mislock audible warnings are enabled.
Alarm sounder Alarm Audible warnings are given by the security system sounder only.
Both Audible warnings are given by both the security system sounder and
the vehicle horn.
Vehicle Audible warnings are given by the vehicle horn only.
BBUS Audible warnings are given by the security system sounder, vehicle
horn and BBUS.
Disabled Audible warnings are not given. Function Option Details

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:
lPerimetric protection – monitors the condition of doors and hinged panels.
lVolumetric protection – monitors the vehicle's interior space.
lRemote locking, superlocking and unlocking functions.
lEngine immobilisation and remobilisation.
lAdvanced mislock detection and automatic compensation.
lEKA code functions.
lCustomer configuration options.
lMarket configuration options.
Immobilisation
The immobilisation system comprises the following components:
lRF receiver.
lRF transmitter/ transponder.
lTransponder coil.
lBCU.
lDoor switches, door lock switches and bonnet switch.
lIDM.
lECM.
lStarter solenoid relay.
lStatus LED.
Alarm system
The alarm system comprises the following components:
lRF receiver.
lRF transmitter.
lBCU.
lIDM.
lDoor switches, door lock switches and bonnet switch.
lBattery backed-up sounder (BBUS).
lStatus 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.

+ 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