2002 LAND ROVER DISCOVERY Road wheel speed sensor

CONTENTS
CONTENTS 3
Alarm handset battery ..................................................................................................................... 10-6
Road wheels ................................................................................................................................... 10-7
Tyres .............................................................................................................................................. 10-7
Brake pads, discs and calipers ....................................................................................................... 10-7
Road wheel speed sensors ............................................................................................................. 10-7
Brake fluid ....................................................................................................................................... 10-8
Fuel filter - diesel engine ................................................................................................................. 10-8
Fuel filter sedimenter ...................................................................................................................... 10-8
Road wheels ................................................................................................................................... 10-8
Radiator/Intercooler ........................................................................................................................ 10-8
Ambient air Temperature and pressure sensor .............................................................................. 10-8
Doors, bonnet and fuel filler flap ..................................................................................................... 10-9
Air suspension intake filter .............................................................................................................. 10-9
Anti-freeze....................................................................................................................................... 10-9
Cooling system ............................................................................................................................... 10-9
Spark plugs - V8 engine.................................................................................................................. 10-10
Air cleaner - V8 engine ................................................................................................................... 10-11
Air cleaner and dump valve - diesel engine .................................................................................... 10-11
Auxiliary drive belt ........................................................................................................................... 10-11
Auxiliary drive belt - V8 engine ....................................................................................................... 10-12
Auxiliary drive belt - diesel engine .................................................................................................. 10-12
Fluid reservoirs ............................................................................................................................... 10-12
Steering box .................................................................................................................................... 10-13
Battery ............................................................................................................................................. 10-13
Intercooler - diesel engine............................................................................................................... 10-14
Engine oil - V8 engine ..................................................................................................................... 10-14
Engine oil - diesel engine ................................................................................................................ 10-14
Centrifuge rotor – diesel engine ...................................................................................................... 10-15
Engine oil filter - diesel engine ........................................................................................................ 10-15
Engine oil filter – V8 engine ............................................................................................................ 10-15
Manual gearbox .............................................................................................................................. 10-16
Automatic gearbox ......................................................................................................................... 10-17
Transfer box .................................................................................................................................... 10-18
Front and rear axle .......................................................................................................................... 10-19
Propeller shafts ............................................................................................................................... 10-19
Anti-roll bar links ............................................................................................................................. 10-20
ACE actuators ................................................................................................................................. 10-21
ACE filter ......................................................................................................................................... 10-21
Brake hose, brake, fuel, ACE, clutch pipes and unions/electrical harnesses ................................ 10-22
Engine, gearbox, transfer box and axles ........................................................................................ 10-23
Exhaust system............................................................................................................................... 10-23
Steering box and front suspension ................................................................................................. 10-23
Steering rod ball joints ................................................................................................................... 10-25
Dampers and SLS height sensors .................................................................................................. 10-25
Front and rear axle suspension links .............................................................................................. 10-26
Towing bracket................................................................................................................................ 10-27
Engine mountings - V8 engine ........................................................................................................ 10-27
Road/roller test................................................................................................................................ 10-28
ENGINE - Td5 ........................................................................................... 12-1-1
DESCRIPTION AND OPERATION
Td5 Engine...................................................................................................................................... 12-1-1
Cylinder block components ............................................................................................................. 12-1-2

MAINTENANCE
PROCEDURES 10-7
Road wheels
Remove
1.Mark the wheel to stud relationship to ensure
that the wheels are refitted in the same
position.
2.Loosen wheel nuts. Raise the vehicle to a
wheel-free condition and remove the wheel
nuts.
Tyres
Check
1.Check tyres for compliance with manufacturer's
specification; visually for cuts, lumps, bulges,
uneven tread wear and depth.
2.Check tyre pressures, condition and tread
depth. Measure the tread depth across the
width of the tyre and around the circumference.
Brake pads, discs and calipers
Check
1. Check front and rear brake pads for wear,
ensure all pads are wearing evenly.
2.Check brake discs for signs of cracking,
excessive scoring or oil contamination.
3.Check calipers for signs of fluid leaks.
4.Clean excessive deposits of brake dust from
pads, calipers and disc shields using brake
cleaner.
Road wheel speed sensors
Inspect
Front wheel
Rear wheel
1.Inspect each sensor harness for damage.

ENGINE MANAGEMENT SYSTEM - V8
DESCRIPTION AND OPERATION 18-2-49
TestBook is able to retrieve the following Catalyst damage fault codes:
The flywheel/ reluctor ring adaptions must be reset if the CKP sensor or the flywheel are changed.
Vehicle Speed Signal (VSS)
The VSS is used, by the ECM, to control idle speed and overrun cut off. The ECM receives the signal through a hard
wired connection direct from the SLABS ECU.
For vehicles fitted with an automatic gearbox, two vehicle speed signals are received by the ECM. The second signal
is derived from the main gearbox output shaft speed, and is sent to the ECM by the Electronic Automatic Transmission
(EAT) ECU though the Controller Area Network (CAN). The ECM compares the vehicle speed signal generated by
the SLABS ECU with that supplied via the CAN.
The ECM also receives transfer box information. This allows the ECM to take in to account the vehicle being driven
using low range gearing and compensate as necessary.
On vehicles with manual transmission, the SLABS signal is checked against a threshold value stored in ECM memory.
If other engine parameters indicate the engine is at high load and the VSS is below the threshold, a fault condition is
registered in the diagnostic memory.
The vehicle speed signal generated by the SLABS ECU is in the form of a pulse width modulated signal (PWM).
Pulses are generated at 8000 per mile, and the frequency of the signal changes in accordance with road speed. At
zero road speed the ECU outputs a reference signal at a frequency of 2Hz for diagnostic purposes.
Function
The input signal for the SLABS ECU is measured via pin 22 of connector C0637 of the ECM. The SLABS ECU
generates a PWM signal switching between 0 and 12 volts at a frequency of 8000 pulses per mile. For vehicles with
automatic gearbox the input signal for the EAT ECU is measured via pins 36 and 37 of connector C0637 of the ECM.
These pin numbers provide a bi-directional communications link using the CAN data bus.
P Code J2012 Description Land Rover Description
P1300 Misfire detected sufficient to cause catalyst
damageCatalyst damaging level of misfire on more than one
cylinder
P1301 No description Catalyst damaging level of misfire detected on cylinder
No.1
P1302 No description Catalyst damaging level of misfire detected on cylinder
No.2
P1303 No description Catalyst damaging level of misfire detected on cylinder
No.3
P1304 No description Catalyst damaging level of misfire detected on cylinder
No.4
P1305 No description Catalyst damaging level of misfire detected on cylinder
No.5
P1306 No description Catalyst damaging level of misfire detected on cylinder
No.6
P1307 No description Catalyst damaging level of misfire detected on cylinder
No.7
P1308 No description Catalyst damaging level of misfire detected on cylinder
No.8

ENGINE MANAGEMENT SYSTEM - V8
18-2-50 DESCRIPTION AND OPERATION
In the case of a VSS failure on vehicles with automatic gearboxes, the ECM applies default values derived from the
EAT ECU. There are no default values for manual gearbox vehicles.
The VSS can fail in the following ways:
lWiring short circuit to vehicle supply.
lWiring short circuit to vehicle earth.
lWiring open circuit.
In the event of a VSS failure, any of the following symptoms may be observed:
lMIL illuminated after 2 driving cycles (NAS only).
lVehicle speed limiting disabled (manual transmission vehicles only).
lSLABS/HDC warning lamp on and audible warning.
Should a malfunction of the component occur the following fault codes may be evident and can be retrieved by
TestBook:
Rough road signal
When the vehicle travels across rough terrain, or on rough roads instability becomes evident in the drive train. The
ECM could interpret these vibrations as a 'false misfire'. To counteract this 'false misfire' the SLABS ECU generates
a rough road signal, sends it to the ECM so that the ECM can suspend misfire detection for as long as the vehicle is
travelling on the 'rough road'.
Function
Input for the rough road signal is measured via pin 34 of connector C0637 of the ECM. The SLABS ECU generates
a PWM signal that varies in accordance with changing road conditions. The rough road PWM signal operates at a
frequency of 2.33 Hz
± 10%. The significance of changes in the PWM signal are shown in the following table:
The rough road signal can fail in the following ways:
lHarness or connector damage
lSLABS failure — wheel speed sensor
A rough road signal failure may be evident from the following:
lHDC / ABS warning light on
P Code J2012 Description Land Rover Description
P0500 Vehicle speed sensor malfunction VSS short or open circuit
P0501 Vehicle speed sensor range/performance VSS implausible
PWM signal Indication
<10% Electrical short circuit to ground
25% ± 5 % Smooth road
50% ± 5 % SLABS error
75% ± 5% Rough road
>90% Electrical short circuit to battery voltage

BRAKES
70-18 DESCRIPTION AND OPERATION
The SLABS ECU continually calculates vehicle speed using the wheel speed inputs from all four ABS sensors. The
calculated vehicle speed is then used as a reference against which individual wheel speeds are monitored for
unacceptable acceleration or deceleration. The ABS sensor inputs are also used by the SLABS ECU to detect vehicle
deceleration rate, vehicle cornering rate and rough terrain.
The engaged forward gear and (on manual gearbox models) the clutch status are computed from the engine data
input, the engine speed input and vehicle speed. Reverse gear status is provided by an input from the reverse lamp
switch (manual gearbox models) or the BCU (automatic gearbox models). On automatic models, the BCU also
provides the neutral selected input.
In addition to controlling the brake related functions, the SLABS ECU:
lControls the operation of the self levelling suspension (SLS) system (where fitted).

+ REAR SUSPENSION, DESCRIPTION AND OPERATION, Description.
lOn V8 models, outputs a rough road signal to the ECM when traversing rough terrain.
lOutputs a vehicle speed signal.
The vehicle speed signal is output to the following systems (where fitted):
lActive Cornering Enhancement.

+ FRONT SUSPENSION, DESCRIPTION AND OPERATION, Description - ACE.
lAir conditioning.

+ AIR CONDITIONING, DESCRIPTION AND OPERATION, Description.
lCruise control.

+ ENGINE MANAGEMENT SYSTEM - Td5, DESCRIPTION AND OPERATION, Description.

+ ENGINE MANAGEMENT SYSTEM - V8, DESCRIPTION AND OPERATION, Description - engine
management.
lEngine management.

+ ENGINE MANAGEMENT SYSTEM - Td5, DESCRIPTION AND OPERATION, Description.

+ ENGINE MANAGEMENT SYSTEM - V8, DESCRIPTION AND OPERATION, Description - engine
management.
lIn-car entertainment.

+ IN CAR ENTERTAINMENT, DESCRIPTION AND OPERATION, Description.
lInstrument pack.

+ INSTRUMENTS, DESCRIPTION AND OPERATION, Description.
ABS sensors
The ABS sensors supply the SLABS ECU with a sinusoidal speed signal from each wheel. An inductive sensor,
installed in the hub bearing of each wheel, senses off a 60 tooth exciter ring integrated into the inner race of the hub
bearing. Each ABS sensor has a fly-lead connecting it to the vehicle wiring.
6 Shuttle valve switches Input
7 Rear left outlet solenoid valve Output
8 Rear left inlet solenoid valve Output
9 Centre differential lock switch Input
10 Rear right outlet solenoid valve Output
11 Rear right inlet solenoid valve Output
12 Brake lamp relay Output
15 Return pump relay Output
C0655
7 Audible warning Output
10 Engine speed Input
Connector and pins not listed are either not used or used by the self levelling suspension system.

+ REAR SUSPENSION, DESCRIPTION AND OPERATION, Description.
Connector/Pin No. Description Input/Output