handbrake LAND ROVER DISCOVERY 2002 Owner's Guide

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

INTERIOR TRIM COMPONENTS
76-3-6 REPAIRS
9.Release handbrake gaiter from console.
10.Remove clip and clevis pin securing cable to
handbrake lever.
11.Move handbrake to fully upward position.
12.Release electric seat switches from console.
13.Disconnect multiplugs from switches and
remove.
14.Remove 2 bolts securing rear of console to
transmission tunnel.
15.Release centre console from fascia.
16.Disconnect multiplug and bulb from cigar
lighter. 17.Remove console.
NOTE: Do not carry out further dismantling if
component is removed for access only.
18.Remove 4 screws securing storage bin lid to
console and remove lid.
19.Release cigar lighter body from console and
remove.
Refit
1.Fit and secure cigar lighter body to console.
2.Fit lid to console and secure with screws.
3.Fit console.
4.Connect multiplug and bulb to cigar lighter.
5.Fit centre console to fascia.
6.Fit 2 bolts securing rear of console to
transmission tunnel.
7.Connect multiplugs to seat switches.
8.Fit switches to console.
9.Move handbrake to lowered position.
10.Fit cable to handbrake and secure with clevis
pin and clip.
11.Fit handbrake gaiter to console.
12.Fit bolts securing forward edge of console to
transmission tunnel.
13. Models with veneer trim: Position veneered
console cover and connect multiplugs to switch
pack. Fit cigar lighter element and secure
veneered console cover to console.
14. Models with base trim: Connect multiplugs to
switch pack, fit switch pack to console and
secure with screws.
15. Models with base trim: Fit cover plate to
switch pack, and rubber mat to console.
16.Fit transfer box gaiter and knob to lever.
17.Secure transfer box gaiter to console.
18.Connect multiplug to selector panel, fit and
secure panel to centre console.
19.Fit spacer and knob to gear selector lever.
20. Models from 03MY:Fit both centre console
cup holders.

INTERIOR TRIM COMPONENTS
76-3-8 REPAIRS
6. Models with veneer trim: Release veneered
console cover from console and remove cigar
lighter element. Disconnect multiplugs from
switch pack and remove veneered console
cover.
7.Remove 2 bolts securing forward edge of
console to transmission tunnel. 8.Release handbrake gaiter from console.
9.Remove clip and clevis pin securing cable to
handbrake.
10.Move handbrake to fully upward position.
11.Release electric seat switches from console.
12.Disconnect multiplugs from switches and
remove.
13.Remove 2 bolts securing rear of console to
transmission tunnel.
14.Release centre console from fascia.
15.Disconnect multiplug and bulb from cigar
lighter.

INTERIOR TRIM COMPONENTS
REPAIRS 76-3-9
16.Remove console.
NOTE: Do not carry out further dismantling if
component is removed for access only.
17.Remove 4 screws securing storage bin lid to
console and remove lid.
18.Release cigar lighter body from console and
remove.
Refit
1.Fit and secure cigar lighter body to console.
2.Fit lid to console and secure with screws.
3.Fit console.
4.Connect multiplug and bulb to cigar lighter.
5.Fit centre console to fascia.
6.Fit 2 bolts securing rear of console to
transmission tunnel.
7.Connect multiplugs to seat switches.
8.Fit switches to console.
9.Move handbrake to lowered position.
10.Fit cable to handbrake and secure with clevis
pin and clip.
11.Fit handbrake gaiter to console.
12.Fit bolts securing forward edge of console to
transmission tunnel.
13. Models with veneer trim: Position veneered
console cover and connect multiplugs to switch
pack. Fit cigar lighter element and secure
veneered console cover to console.
14. Models with base trim: Connect multiplugs to
switch pack, fit switch pack to console and
secure with screws.
15. Models with base trim: Fit cover plate to
switch pack, and rubber mat to console.
16.Fit transfer gearbox gaiter and knob to lever.
17.Secure gaiter to console.
18.Fit knob and gaiter to gear lever and secure
gear lever gaiter to console with clips.
19. Models from 03MY:Fit both centre console
cup holders.
Fascia
$% 76.46.23/99
Remove
1.Remove the key from the starter switch.
Disconnect both battery leads, negative lead
first. Wait ten minutes before starting work.
2.Remove radio cassette player.

+ IN CAR ENTERTAINMENT,
REPAIRS, Radio cassette player.
3.Remove steering wheel.

+ STEERING, REPAIRS, Steering
wheel.
4.Remove steering column nacelle.

+ STEERING, REPAIRS, Nacelle -
steering column.
5.Remove centre console.
lFor models with automatic gearbox:

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Console - centre - automatic
models.
lFor models with manual gearbox:

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Console - centre - manual
models.
6.Remove 'A' post trim panels.

HARNESSES
86-7-26 REPAIRS
82.Remove nut securing earth header to footwell.
83.Remove earth header.
84.Remove clip securing harness to pedal box. 85.Remove 2 nuts securing harness to tunnel.
86.Disconnect Lucar from handbrake switch.
87.Disconnect multiplug from DCU.
88.Remove rear carpet.

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Carpet - rear.

HARNESSES
REPAIRS 86-7-27
89.Disconnect 3 multiplugs from RH rear door
harness.
90.Remove 2 nuts securing 2 earth headers to
rear centre console tunnel.
91.Remove earth headers from centre console.
92.Disconnect multiplug from CD player.
93.Remove 5 clips and 2 retainers securing
harness to floor. 94.Disconnect 3 multiplugs from LH rear door
harness.
95.Withdraw harness to interior.
96.Manoeuvre harness over steering column
support bracket.
97.With assistance remove main harness.
Refit
1.With assistance position main harness to body
and manoeuvre over steering column support
bracket.
2.Lay harness in position and secure to floor
clips and retainers.
3.Connect LH and RH rear door multiplugs.
4.Connect CD player multiplug.
5.Position centre console earth headers and
secure with nuts.
6.Fit rear carpet.

+ INTERIOR TRIM COMPONENTS,
REPAIRS, Carpet - rear.
7.Connect DCU multiplug.
8.Connect Lucar to handbrake switch.
9.Fit and tighten nuts securing harness to
transmission tunnel.
10.Secure harness to pedal box.
11.Position footwell earth header and secure with
nut.
12.Feed RH side of harness into engine bay.
13.Position carpet.
14.Connect wiper motor multiplug, position
mechanism and secure with nuts and bolts.
15.Connect ECM multiplug.
16.Position RH lower 'A' post earth header and
secure with nut, connect cruise control
multiplug.
17.Connect RH front door and RH side body
harness multiplugs.