warning LAND ROVER DISCOVERY 2002 Workshop Manual

BRAKES
70-44 REPAIRS
Refit
1.Rotate disc by hand and scrape all scale and
rust from around edge of disc. Clean location
surfaces on caliper bracket.
2.Clean dust from brake parts using brake
cleaning fluid.
WARNING: Do not use compressed air to
clean brake components. Dust from friction
materials can be harmful if inhaled.
3.Fit brake pads to caliper carrier.
4.Position caliper housing to carrier, align flats on
guide pins with caliper housing.
5.Fit guide pin bolts and tighten to 30 Nm (22
lbf.ft).
6.Clean banjo bolt and fit new sealing washers.
7.Position hose to caliper and tighten banjo bolt
to 32 Nm (24 lbf.ft).
8.Remove clamp from brake hose.
9.Bleed brake system.

+ BRAKES, ADJUSTMENTS, Brake
system bleeding.
10.Fit road wheel(s) and tighten nuts to 140 Nm
(103 lbf.ft).
11.Remove stand(s) and lower vehicle.
Housing - caliper - rear
$% 70.55.25
Remove
1.Raise rear of vehicle, one side.
WARNING: Do not work on or under a
vehicle supported only by a jack. Always
support the vehicle on safety stands.
2.Remove road wheel(s).
3.Clamp brake hose to prevent fluid loss.
4.Remove brake hose banjo bolt and discard
sealing washers.
CAUTION: Always fit plugs to open
connections to prevent contamination.
5.Remove 2 guide pin bolts and remove caliper
housing from carrier.
6.Remove 2 brake pads from caliper carrier.

BRAKES
REPAIRS 70-45
Refit
1.Rotate disc by hand and scrape all scale and
rust from around edge of disc. Clean location
surfaces on caliper bracket.
2.Clean dust from brake parts using brake
cleaning fluid.
WARNING: Do not use compressed air to
clean brake components. Dust from friction
materials can be harmful if inhaled.
3.Fit brake pads to caliper carrier.
4.Position caliper housing to carrier, align flats on
guide pins with caliper housing.
5.Fit guide pin bolts and tighten to 30 Nm (22
lbf.ft).
6.Clean banjo bolt and fit new sealing washers.
7.Position hose to caliper and tighten banjo bolt
to 32 Nm (24 lbf.ft).
8.Remove clamp from brake hose.
9.Bleed brakes.

+ BRAKES, ADJUSTMENTS, Brake
system bleeding.
10.Fit road wheel(s) and tighten nuts to 140 Nm
(103 lbf.ft).
11.Remove stand(s) and lower vehicle.
ECU - Self levelling and anti locking
brakes (SLABS)
$% 70.65.01
Remove
1.Remove BCU.

+ BODY CONTROL UNIT, REPAIRS,
Body control unit (BCU).
2.Remove 5 multiplugs from SLABS ECU.
3.Remove multiplug from ACE ECU.
4.Remove lower nut and loosen upper nut
securing SLABS and ACE ECU bracket to
body.
5.Remove ECU's and bracket assembly.

BRAKES
REPAIRS 70-49
Switch - handbrake
$% 86.65.45
Remove
1.Remove centre console.

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Console - centre - automatic
models.

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Console - centre - manual
models.
2.Disconnect Lucar from handbrake warning
switch.
3.Remove clip and clevis pin securing cable to
handbrake lever.
4.Remove 2 bolts and remove handbrake lever.
5.Remove 2 screws securing switch to
handbrake lever and remove switch.
Refit
1.Fit switch to handbrake lever and tighten
screws.
2.Position handbrake lever to floor and tighten
bolts to 22 Nm (16 lbf.ft).
3.Align cable to handbrake lever and fit clevis pin
and clip.
4.Connect Lucar to handbrake switch.
5.Fit centre console.

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Console - centre - automatic
models.

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Console - centre - manual
models.

RESTRAINT SYSTEMS
DESCRIPTION AND OPERATION 75-1
RESTRAINT SYSTEMS DESCRIPTION AND OPERAT ION
SRS component layout
RHD shown, LHD similar
1DCU
2SRS warning lamp
3Driver airbag module
4Driver seat belt pretensioner
5Passenger airbag module
6Passenger seat belt pretensioner

RESTRAINT SYSTEMS
75-2 DESCRIPTION AND OPERATION
SRS block diagram
1DCU
2SRS warning lamp
3Driver airbag module
4Driver seat belt pretensioner
5Passenger airbag module
6Passenger seat belt pretensioner

RESTRAINT SYSTEMS
DESCRIPTION AND OPERATION 75-3
Description - SRS
General
The purpose of the Supplementary Restraint System (SRS) is to reduce the impact of the driver and passenger
against the vehicle's interior in the event of a serious accident.
The SRS system is a stand-alone system. There are no remotely mounted crash sensors. The only external input to
the DCU is power. The system only becomes live when the ignition is switched on.
The SRS consists of the following components:
lDiagnostic and control unit (DCU).
lSRS warning lamp.
lRotary coupler.
lDriver airbag module.
lDriver seat belt pretensioner.
lPassenger airbag module.
lPassenger seat belt pretensioner.
The passenger airbag is optional in some markets. All other components are standard fit in all markets. The SRS
functions the same in all markets.

RESTRAINT SYSTEMS
DESCRIPTION AND OPERATION 75-7
SRS warning lamp
The SRS warning lamp located in the instrument cluster indicates the following:
lThe status of the system readiness check on start-up.
lA fault within the SRS system.
The input to the SRS warning lamp from the DCU is 12 volts during the readiness test, 0 volts if no fault present and
12 volts if a fault is detected.
The DCU is capable of detecting an open circuit or a short circuit for the SRS warning lamp.
The DCU also stores the following additional information on each fault:
lA count indicating the number of times the fault occurred.
lA start and end time for the fault to indicate the duration of the fault.

RESTRAINT SYSTEMS
75-8 DESCRIPTION AND OPERATION
Diagnostic and Control Unit (DCU)
The SRS DCU is an electronic single point crash sensor. It is capable of sensing if a crash has taken place. If all the
relevant parameters are met, then the DCU deploys the airbag(s) and seat belt pretensioners.
The DCU is bolted to the transmission tunnel beneath the centre console in the area of the handbrake.
The DCU performs the following functions:
lInternal self test, system monitoring and fault detection.
lSRS warning lamp operation.
lSystem deployment.
Self test, system monitoring and fault detection
The DCU performs a self-test during start-up and then continually during operation of the system. The following
components are tested:
lThe decelerometer.
lThe electromechanical safing sensor.
lThe microprocessor.
lThe continuity of squib ignition circuits.
lThe SRS warning lamp.
If the DCU detects a fault, it stores the fault code in memory. Diagnose the DCU with TestBook. The DCU cannot
be serviced. It must be replaced if it is faulty.
SRS warning lamp operation
The DCU controls the SRS warning lamp contained in the instrument cluster.
System deployment
The DCU determines when the system deploys based on inputs from both the decelerometer and the
electromechanical safing sensor. Both are located within the DCU. Neither are serviceable.
The electromechanical safing sensor uses a magnet and ball bearing system to provide a mechanical confirmation of
vehicle deceleration. The ball bearing is held in place by the magnet. The strength of the magnet is calibrated such
that the force required for the ball bearing to move away from the magnet will only occur if the vehicle decelerates
suddenly, as in an accident.
The SRS deploys only if both the decelerometer reading and the safing sensor operation occur at the same time.

RESTRAINT SYSTEMS
DESCRIPTION AND OPERATION 75-9
Operation - SRS
The diagnostic and control unit (DCU) controls the SRS system. The DCU is located beneath the centre console close
to the handbrake area. The DCU contains both an electronic deceleration sensor as well as an electromechanical
safing sensor. When the electronic deceleration sensor within the DCU detects rapid deceleration of the vehicle, it
compares the deceleration rate with stored values in its' memory. If the deceleration rate exceeds the stored value
and the electromechanical safing sensor triggers, the DCU deploys the airbag and the seat belt pretensioners. The
DCU will not deploy the airbags and seat belt pretensioners unless both sensors trigger.
The SRS has diagnostic capabilities through TestBook. In the event that a fault is detected, the DCU alerts the driver
by illuminating a warning lamp in the instrument cluster.
The DCU controls the following:
lSRS warning lamp.
lDrivers airbag module.
lPassenger airbag module (where fitted).
lDriver seat belt pretensioner.
lPassenger seat belt pretensioner.
WARNING: The integrity of the SRS system are critical for safety reasons. Ensure the following precautions
are always adhered to:
lNever install used SRS components from another vehicle or attempt to repair an SRS component.
lWhen repairing an SRS system only use genuine new parts.
lNever apply electrical power to an SRS component unless instructed to do so as part of an approved test
procedure.
lSpecial Torx bolts are necessary for installing the airbag module - do not use other bolts. Ensure bolts
are tightened to the correct torque.
lAlways use new fixings when replacing an SRS component.
lEnsure the SRS Diagnostic Control Unit (DCU) is always installed correctly. There must not be any gap
between the DCU and the bracket to which it is mounted. An incorrectly mounted DCU could cause the
system to malfunction.
System deployment
The airbag and seat belt pretensioners deploy to protect the front seat occupants when the DCU senses a rapid
vehicle deceleration. The system deploys when the following conditions are met:
lThe ignition switch is on.
lThe vehicle decelerates beyond a threshold defined within the DCU.
lThe electromechanical safing sensor within the DCU triggers.
When all of the above conditions are met, the DCU deploys the airbag(s) and seat belt pretensioners. If the above
conditions are not met, the DCU will not deploy the system.
Component replacement policy
After an impact which deploys the airbags and pretensioners, the following components must be renewed:
lDCU.
lDriver and passenger airbag modules.
lDriver and passenger buckle pretensioners.
lRotary coupler.
lFlyleads (where applicable) connecting airbags and pre-tensioners to SRS harness

RESTRAINT SYSTEMS
75-10 DESCRIPTION AND OPERATION
SRS warning lamp
The SRS warning lamp illuminates for 5 seconds during system readiness check on starting the engine. The SRS
warning lamp extinguishes for one second after the system readiness check is performed. If a fault is present the
warning lamp then illuminates continuously. If no fault is present, the SRS warning lamp remains extinguished. If a
system fault occurs in excess of two seconds after the readiness check has been completed, the SRS warning lamp
illuminates for that ignition cycle. It remains illuminated for a minimum of 12 seconds
± 4 seconds for all fault
conditions.
The SRS warning lamp will only illuminate for low voltage concerns while the low voltage condition is present. If the
low voltage condition is corrected, the SRS warning lamp extinguishes and the fault is recorded in the DCU's memory.