2002 LAND ROVER DISCOVERY manual transmission

ENGINE MANAGEMENT SYSTEM - V8
18-2-48 DESCRIPTION AND OPERATION
Misfire detection
Due to increasing legislation, all new vehicles must be able to detect two specific levels of misfire.
Conditions
The ECM is able to carry out misfire detection as part of the OBD system using the following component parts:
lFlywheel reluctor adaptation.
lCalculation of engine roughness.
lDetection of excess emissions misfire.
lDetection of catalyst damaging misfire.
Function
The flywheel/ reluctor ring is divided into four segments 90
° wide. The ECM misfire detection system uses information
generated by the CKP to determine crankshaft speed and position. If a misfire occurs, there will be an instantaneous
slight decrease in engine speed. The ECM misfire detection system is able to compare the length of time each 90
°
segment takes and is therefore able to pinpoint the source of the misfire.
For the ECM misfire detection system to be calibrated for the tolerances of the reluctor tooth positions, the flywheel/
reluctor ring must be 'adapted' as follows:
l1800 - 3000 rev/min = speed range 1.
l3000 - 3800 rev/min = speed range 2.
l3800 - 4600 rev/min = speed range 3.
l4600 - 5400 rev/min = speed range 4.
The ECM carries out flywheel/ reluctor ring adaptions across all the above speed ranges and can be monitored by
TestBook. The test should be carried out as follows:
lEngine at normal operating temperature.
lSelect second gear (for both automatic and manual transmission vehicles).
lAccelerate until engine rev limiter is operational.
lRelease throttle smoothly to allow engine to decelerate throughout the speed ranges.
lRepeat process as necessary until all adaptations are complete.
TestBook is able to retrieve the following misfire detection fault codes:
P Code J2012 Description Land Rover Description
P0300 Random/multiple cylinder misfire detected Excess emissions level of misfire on more than one
cylinder
P0301 Cylinder 1 misfire detected Excess emissions level of misfire detected on cylinder
No.1
P0302 Cylinder 2 misfire detected Excess emissions level of misfire detected on cylinder
No.2
P0303 Cylinder 3 misfire detected Excess emissions level of misfire detected on cylinder
No.3
P0304 Cylinder 4 misfire detected Excess emissions level of misfire detected on cylinder
No.4
P0305 Cylinder 5 misfire detected Excess emissions level of misfire detected on cylinder
No.5
P0306 Cylinder 6 misfire detected Excess emissions level of misfire detected on cylinder
No.6
P0307 Cylinder 7 misfire detected Excess emissions level of misfire detected on cylinder
No.7
P0308 Cylinder 8 misfire detected Excess emissions level of misfire detected on cylinder
No.8

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

ENGINE MANAGEMENT SYSTEM - V8
DESCRIPTION AND OPERATION 18-2-51
Should a malfunction of the rough road signal occur, the following fault codes may be evident and can be retrieved
by TestBook:
Hill Descent Control (HDC) signal
The ECM transmits throttle angle, engine torque, engine identification (Td5 or V8), and transmission type (automatic
or manual) data to the SLABS ECU to support the Hill Descent Control system. The information is transmitted via a
0 – 12V pulse width modulated (PWM) signal at a frequency of 179.27 Hz.
Function
The HDC signal output from the ECM is via pin 29 of connector C0636. The ECM generates a PWM signal that varies
in pulse width in accordance with changing throttle angle or engine torque. The throttle angle data is transmitted on
pulses 1, 3, 5 and 37. The engine torque data is transmitted on pulses 2,4,6 and 38. The engine and transmission
information is transmitted on pulse 39. A synchronising pulse is transmitted after every 39th pulse.
The HDC signal can fail in the following ways:
lHarness or connector damage
A HDC signal failure may be evident from the following:
lHDC / ABS warning light on
lHDC inoperative
lAudible warning
Should a malfunction of the HDC signal occur, the following fault codes may be evident and can be retrieved by
TestBook:
Low fuel level signal
When the fuel level in the fuel tank becomes low enough to illuminate the low fuel level warning lamp in the instrument
cluster, the instrument cluster generates a low fuel level signal. If the low fuel level signal is present during the ECM
misfire detection function the ECM can use it to check for a 'false misfire'.
Conditions
The fuel sender generates the low fuel level signal when the fuel sender resistance is greater than 158
± 8 ohms.
P Code J2012 Description Land Rover Description
P1590 ABS rough road signal circuit malfunction Hardware is OK, but SLABS ECU is sending an error
signal
P1591 ABS rough road signal circuit low Signal from SLABS ECU short circuit to earth
P1592 ABS rough road signal circuit high Signal from SLABS ECU short circuit to vehicle battery
supply
P Code J2012 Description Land Rover Description
P1663 Throttle angle/Torque signal circuit malfunction SLABS HDC link open circuit
P1664 Throttle angle/Torque signal circuit low SLABS HDC link short circuit to ground
P1665 Throttle angle/Torque signal circuit high SLABS HDC link short circuit to battery voltage

ENGINE MANAGEMENT SYSTEM - V8
DESCRIPTION AND OPERATION 18-2-53
Function
The CAN system uses a twisted pair of wires to form the 'data bus' to minimise electrical interference. This method of
serial interface is very reliable and very fast. The information messages are structured so that each of the receivers
(ECM or EAT ECU) is able to interpret and react to the messages sent.
The CAN 'data bus' is directly connected between pin 36 of connector C0637 of the ECM and pin 16 of connector
C0193 at the EAT ECU, and pin 37 of connector C0637 of the ECM and pin 44 of connector C0193 at the EAT ECU.
The CAN system can fail in the following ways:
lCAN data bus wiring open circuit.
lCAN data bus wiring short circuit.
In the event of a CAN data bus failure any of the following symptoms may be observed:
lMIL illuminated after 2 drive cycles (NAS only).
lEAT defaults to 3rd gear only.
lHarsh gearshifts.
l'Sport' and 'manual' lights flash alternately.
Should a malfunction of the component occur the following fault codes may be evident and can be retrieved by
TestBook.
Drive cycles
The following are the TestBook drive cycles:

Drive cycle A:
1Switch on the ignition for 30 seconds.
2Ensure engine coolant temperature is less than 60
°C (140°F).
3Start the engine and allow to idle for 2 minutes.
4Connect TestBook and check for fault codes.

Drive cycle B:
1Switch ignition on for 30 seconds.
2Ensure engine coolant temperature is less than 60
°C (140°F).
3Start the engine and allow to idle for 2 minutes.
4Perform 2 light accelerations (0 to 35 mph (0 to 60 km/h) with light pedal pressure).
5Perform 2 medium accelerations (0 to 45 mph (0 to 70 km/h) with moderate pedal pressure).
6Perform 2 hard accelerations (0 to 55 mph (0 to 90 km/h) with heavy pedal pressure).
7Allow engine to idle for 2 minutes.
8Connect TestBook and with the engine still running, check for fault codes.
P Code J2012 Description Land Rover Description
P0600 Serial communication link malfunction CAN time out
P1776 Transmission control system torque interface
malfunctionEAT torque interface error

AUTOMATIC GEARBOX - ZF4HP22 - 24
44-10 DESCRIPTION AND OPERATION
The lock-up and brake clutches are operated by pressurised transmission fluid from the valve block in the sump. A
manual valve and four solenoid valves, also known as Motorised Valves (MV), control the supply of pressurised
transmission fluid from the valve block:
lThe manual valve controls the supply in P, R, N and D.
lSolenoid valves MV 1 and MV 2 control the supplies that operate the brake clutches for shift control.
lSolenoid valve MV 3 controls the supply that operates the lock-up clutch.
lSolenoid valve MV 4 modulates the pressure of the supplies to the brake clutches, to control shift quality.
Operation of the manual valve is controlled by the selector lever assembly. In the gearbox, a selector shaft engages
with the manual valve. The selector shaft is connected to the selector lever assembly via the selector cable and a
selector lever on the left side of the gearbox. The selector shaft also operates a mechanism that locks the output shaft
when P is selected.
Operation of the solenoid valves is controlled by the EAT ECU.
An output shaft speed sensor in the gearbox housing outputs a signal to the EAT ECU. The EAT ECU compares
output shaft speed with engine speed to determine the engaged gear, and output shaft speed with vehicle speed to
confirm the range selected on the transfer box.
A bayonet lock electrical connector in the gearbox casing, to the rear of the selector lever, connects the solenoid
valves and the output shaft speed sensor to the vehicle wiring.
A pressed steel sump encloses the valve block and collects transmission fluid draining from the gearbox housing. A
suction pipe and filter on the underside of the valve block connect to the inlet side of the fluid pump. A magnet is
installed in the sump to collect any magnetic particles that may be present. A level plug and a drain plug are installed
in the sump for servicing.
Rear extension housing
The rear extension housing provides the interface between the gearbox housing and the transfer box. A splined
extension shaft, secured to the gearbox output shaft by a bolt, transmits the drive from the gearbox to the transfer
box. A seal in the rear of the housing prevents leakage past the extension shaft. A breather pipe, attached to the left
side of the rear extension housing, ventilates the interior of the gearbox and rear extension housings to atmosphere.
The open end of the breather pipe is located in the engine compartment at the right front corner of the engine sump
on gearboxes fitted to early vehicles and is clipped to the top of the gearbox on later vehicles.
Gearbox power flows
The following Figures show the power flow through the gearbox for each forward gear when D is selected, and for
reverse. The key to the Item numbers on the Figures, and in parenthesis in the accompanying text, can be found on
the 'Sectioned view of gearbox' Figure, above.
1st Gear (D selected)
Clutches (4) and (11) are engaged. The front planet gear carrier of gear set (9) locks against the gearbox housing
through freewheel (15) when the engine powers the vehicle, and freewheels when the vehicle is coasting. Gear set
(10) rotates as a solid unit with the front planet gear carrier. In 1st gear hold brake clutch (8) is applied to provide
overrun braking.

AUTOMATIC GEARBOX - ZF4HP22 - 24
44-14 DESCRIPTION AND OPERATION
EAT ECU connector
EAT ECU connector pin details
Pin No. Description Inputs/Outputs
1 to 4 Not used-
5 Pressure regulator solenoid valve (MV 4) Output
6 Power earth -
7 Not used-
8 Gear position switch, X contacts Input
9 Gear position switch, Z contacts Input
10 to 12 Not used-
13 Transmission high/low switch Input
14 Gearbox output shaft speed sensor, negative Input
15 Gearbox output shaft speed sensor cable screen -
16 CAN, high Input/Output
17 to 24 Not used-
25 Sport mode warning lamp Output
26 Battery power supply Input
27 Not used-
28 Electronics earth -
29 Not used-
30 Shift control solenoid valve (MV 1) Output
31 Diagnostics, K line Input/Output
32 Converter lock-up solenoid valve (MV 3) Output
33 Shift control solenoid valve (MV 2) Output
34 Not used-
35 Not used-
36 Gear position switch, W contacts Input
37 Gear position switch, Y contacts Input
38 to 41 Not used-
42 Gearbox output shaft speed sensor, positive Input
43 Not used-
44 CAN, low Input/Output
45 Mode switch Input
46 to 50 Not used-
51 Manual mode warning lamp Output
52 Not used-
53 Solenoid valves power supply Output
54 Ignition power supply Input
55 Not used-

AUTOMATIC GEARBOX - ZF4HP22 - 24
44-16 DESCRIPTION AND OPERATION
Warning lamps
Warning lamps and selector lever position indication
1Transmission temperature warning lamp (red)
2Gear selector lever position indication
3Sport mode warning lamp (green)
4Manual mode warning lamp (green)
Illumination for each warning lamp is provided by a non serviceable LED.