Land Rover Discovery 99my To 03my Electrical Library 3rd Edition Rover Manual

DESCRIPTION AND OPERATION
4.70DISCOVERY SERIES II
ANTI-LOCK BRAKING SYSTEM (ABS)
DESCRIPTION
General
ABS is controlled by the Self Levelling and Anti-lock Braking System (SLABS) ECU. The 
ABS system comprises the ECU, ABS wheel sensors and an ABS modulator. The ABS 
system also controls electronic brake distribution, hill descent control, centre differential lock 
control and electronic traction control. Refer to Workshop Manual - Description and 
Operation for further details.
NOTE: This Description and...

DESCRIPTION AND OPERATION
DISCOVERY SERIES II 4.71
ABS Operation
HDC Brake lamp operation
When the hill descent control operates, the SLABS ECU pin C0506-12 provides a power 
supply on a BG wire to the coil of the hill descent relay in the passenger compartment 
fusebox. The relay coil energises and the contacts close. The earth path from the coil is from 
the passenger compartment fusebox on a B wire to earth header C0017 LHD/C0018 RHD.
The feed from fuse 25 in the passenger compartment fusebox passes...

DESCRIPTION AND OPERATION
4.72DISCOVERY SERIES II
Transmission high/low switch operation
When the transmission high/low switch is operated, an earth path is completed from the 
SLABS ECU pin C0504-11, via header C0290 LHD/C0288 RHD to the transmission high/
low switch on an RK wire.
On vehicles with automatic transmission, the earth path is completed from the switch on a 
B wire to splice joint SJ2. From the splice joint the earth is connected on a B wire to earth 
header C0552.
On vehicles with manual...

DESCRIPTION AND OPERATION
DISCOVERY SERIES II 4.73
Instrument pack
The SLABS ECU provides outputs to the instrument pack through connector C0504. The 
outputs are as follows:
zFrom SLABS ECU pin C0504-16 to instrument pack pin C0233-5 on a WY wire (HDC 
warning lamp)
zFrom SLABS ECU pin C0504-17 to instrument pack pin C0233-10 on a WK wire (HDC 
info warning lamp)
zFrom SLABS ECU pin C0504-18 to instrument pack pin C0233-3 on a WR wire (ABS 
warning lamp)
zFrom SLABS ECU pin C0504-13 to instrument pack...

DESCRIPTION AND OPERATION
4.74DISCOVERY SERIES II
Road speed signal
The SLABS ECU outputs a road speed signal from pin C0504-3 on a KG wire to header 
C0290. From header C0290 the road speed signal is passed on KG wires to the following 
ECU pins:
zCruise control ECU pin C0239-15
zEngine Control Module (ECM pin C0637-22 on V8 engine vehicles and pin C0658-13 
on Td5 engine vehicles
zActive Cornering Enhancement (ACE) ECU pin C0647-5
zICE Tuner/Amplifier pin C0491-20
zInstrument pack pin C0230-16
zAir...

DESCRIPTION AND OPERATION
DISCOVERY SERIES II 4.75
SUPPLEMENTARY RESTRAINT SYSTEM (SRS)
DESCRIPTION
General
The Supplementary Restraint System (SRS) provides additional protection for front seat 
occupants during a frontal collision above a preset severity.
The system is operational only with the ignition switch in position II. With the ignition on, any 
frontal collision is detected by an accelerometer and a mechanical safing sensor within the 
airbag DCU. If the impact is above the preset severity, the...

DESCRIPTION AND OPERATION
4.76DISCOVERY SERIES II
OPERATION
SRS Supply
Circuit supply
A feed from the battery positive terminal is connected on an R wire to the engine 
compartment fusebox where it passes through fusible link 8.
A feed from fusible link 8 is connected on an NW wire to the passenger compartment 
fusebox and from the fusebox to the ignition switch (S176) on an N wire.
Ignition switch supply
With the ignition switch in position II, the feed from fusible link 8 passes through the ignition...

DESCRIPTION AND OPERATION
DISCOVERY SERIES II 4.77
AIR CONDITIONING (A/C)
DESCRIPTION
General
The air conditioning (A/C) can only be operated with the engine running. The A/C is selected 
using the Air Temperature Control (ATC) panel on the fascia. The A/C system controls the 
temperature, distribution and volume of air supplied to the vehicle interior. The system is 
electronically controlled with automatic and manual modes of operation. The system also 
features separate temperature control of the LH...

DESCRIPTION AND OPERATION
4.78DISCOVERY SERIES II
Ignition switch supply
When the ignition switch is in position II, the feed from fusible link 8 flows through the ignition 
switch to the passenger compartment fusebox on a W wire and passes through fuse 31.
From fuse 31 the feed passes on a GK wire to splice joint A9/A144. From the splice joint the 
feed is divided into three separate feeds as follows:
zA GK wire supplies power to the Air Temperature Control (ATC) ECU.
zA GR wire supplies power to the...

DESCRIPTION AND OPERATION
DISCOVERY SERIES II 4.79
Air conditioning compressor clutch relay supply
A feed from fuse 6 in the engine compartment fusebox, is connected to the contacts of the 
air conditioning compressor clutch relay.
Air conditioning compressor clutch operation
When the main relay is energised, a feed passes from the relay contacts to the coil of the air 
conditioning compressor clutch relay. The compressor clutch relay coil is earthed on a BS 
wire to the ECM.
When conditions are correct,...