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Range Rover 2. Electrical Manual - part 171

IGNITION AND SHIFT INTERLOCK

CIRCUIT DIAGRAM

REV: 08/99

Z238
Body Electrical
Control Module
(BECM)

C1276

C0075

[1]

X168
Stop Lamp
Switch

[1]

Brake Pedal
Depressed

[1]

S211

See Fuse Details

C1280

X134
Ignition Switch

III

C0028

See Ground
Distribution

E0562

C0028

C1276

S201

C0075

Anti–Lock Brake
System

F 17

10 A

1 =

0 =

* =

Switch Open

Switch Closed

Fault

X294
Gear Box
Position Switch

[1]

X Switch

[2]

Y Switch

[3]

Z Switch

[1]

See Ground
Distribution

E0808

C0244

[2]

C0745

C1287

[3]

C0244

C0988

S608

S609

S610

Automatic
Gearbox

C0988

C0745

IGNITION AND SHIFT INTERLOCK

CIRCUIT DIAGRAM

REV: 11/99

See Fuse Details

X298
Transfer Micro
Switch/Shift Lock
Solenoid

[1]

Transfer
Micro Switch

[2]

Lo Range
Selected

[3]

Shift Lock
Solenoid
(with Shift
Lock only)

[4]

Park Switch

Transfer Gearbox

C1290

[2]

Z238
Body Electrical
Control Module
(BECM)

[1]

[3]

S607

E0808

S611

See Ground
Distribution

C1279

[1]

C0672

X229
Key–In Switch

[1]

Key
Inserted

F 13

20 A

[4]

C0673

P125a
Engine
Compartment
Fuse Box

C0574

C0069

K191
Ignition Key Lock
Solenoid

C0069

10 A

F 42

C0229
C0069

C0868
C0903

C0672

E0562

See Fuse Details

Z294
Ignition Key Lock
Solenoid Diode

S228

S229

(MY 2000)

KEY INFORMATION

Component is disconnected.

Backprobe harness connector

Component is connected.

Backprobe harness connector

Component is disconnected.

Probe component

Component is disconnected.

Probe harness connector

Probe inĆline connector

TERMINAL

NUMBER

DESIGNATION

Battery voltage: Ignition Switch

in position III

Battery voltage: supplied constantly

Battery voltage: Ignition Switch

in position II or III

Battery voltage: Ignition Switch

in positions I, II

Ground

CIRCUIT DIAGRAMS

Circuit diagrams are arranged so that

current flow is from the top of the diagram

(current source) to the bottom of the

diagram (ground).

D Only those components that work together

in the circuit are shown. If only part of a

component is used in the circuit, then only

that part of the component is shown.

D Remember:

Entire component

Part of a component

DIAGNOSIS

If the diagram is accompanied by text:

- Read the Circuit Operation before

proceeding with the electrical diagnosis.

- Read the Troubleshooting Hints before

performing the System Diagnosis.

- Tests follow the System Diagnosis

- When performing the System Diagnosis,

be certain that all components

disconnected in previous steps are

reconnected unless otherwise directed.

See Introduction (i) for additional

circuit diagram symbols.

ANTI-LOCK BRAKE SYSTEM

CIRCUIT OPERATION

REV: 11/2000

CIRCUIT OPERATION

The Anti–lock Braking System (ABS) prevents wheel
lock–up during braking. This enables the driver to
maintain vehicle stability and steering control while
braking.

The Electronic Traction Control (ETC) system
prevents wheel slip to maintain optimum traction on
slippery surfaces. Up to 99 Model Year, ETC
operates only on the rear wheels at vehicle speeds
below 50 km/h (30 mph). From 99 Model Year, ETC
operates on all four wheels at vehicle speeds below
100 km/h (62.5 mph).

Anti–lock Braking System Electronic Control Unit
(ECU) (Z108)

The ABS ECU (Z108) is a computer that controls
ABS operation by permanently monitoring the
vehicle’s four wheel speeds when the ignition switch
is in position II. If an impending wheel lock–up is
detected during this monitoring, the ABS ECU will
apply voltage to the applicable inlet and outlet valve
solenoids contained in the ABS Booster Unit (Z103).
Operation of the solenoid valves regulates the
pressure applied to the brake caliper and prevents
wheel lock–up.

ETC is an extension to the ABS ECU. In addition to
monitoring the wheel speeds for lock–up, the ABS
ECU also monitors wheel speeds for wheel slip (i.e.
wheel speed faster than vehicle speed). When wheel
slip is detected, the ABS ECU will apply braking
pressure to the slipping wheel(s), causing the wheel
speed to slow to vehicle speed and torque to be
transferred to the non–slipping wheel(s). The ABS
ECU applies the brake by operating the applicable
inlet and outlet solenoid valves in the ABS Booster
Unit.

The ABS ECU has diagnostic capabilities that allow
it to detect faults that may impair the system’s
efficiency. If a fault occurs, the ECU adopts a default
strategy which illuminates the ABS or the TC
warning light in the instrument cluster (Z142) and
stores a fault code in its memory to aid system
troubleshooting. When an ABS fault has been
detected, the message ABS FAULT may also be
displayed in the instrument cluster message centre.
When an ETC fault has been detected, the message
TRACTION FAILURE is displayed and on the first
detected fault a single audible chime sounds. Fault
codes stored in the ECU memory can be retrieved
using Testbook or a universal scan tool.

The ABS ECU also performs a bulb check of the
warning lights when the ignition switch is first turned
to position II. The ABS warning light is illuminated for
1 second, extinguished for 0.5 seconds and
illuminated again until the ECU receives an input
speed of 7 km/h (5 mph) from all four wheel speed
sensors (X137, X140, X1158, X161) and is then
extinguished. The TC warning light is illuminated for
3 seconds and then extinguished. If a system fault is
detected during the bulb check the ABS or the TC
warning light remain illuminated.

When ETC is activated, the TC warning light
illuminates, a single audible chime sounds and on
earlier models, the message TRACTION is
displayed. The message and warning light extinguish
after 2 seconds minimum or when ETC is
de–activated. If ETC is continuously or repeatedly
active and there is a risk of the brakes overheating
the ABS ECU disables the ETC. To advise the driver
of the disablement, the ETC warning light flashes for
10 seconds minimum, a single audible chime sounds
and the message TRACTION OVERHEAT is
displayed. The ABS ECU restores ETC availability
after allowing time for the brakes to cool.

Content .. 169 170 171 172 ..