fuel type LAND ROVER DISCOVERY 2002 Owner's Manual
[x] Cancel search | Manufacturer: LAND ROVER, Model Year: 2002, Model line: DISCOVERY, Model: LAND ROVER DISCOVERY 2002Pages: 1672, PDF Size: 46.1 MB
Page 376 of 1672
EMISSION CONTROL - V8
DESCRIPTION AND OPERATION 17-2-39
Possible symptoms associated with a purge valve or associated pipework failure is listed below:
lEngine may stall on return to idle if purge valve is stuck open.
lPoor idling quality if the purge valve is stuck open
lFuelling adaptions forced excessively lean if the EVAP canister is clear and the purge valve is stuck open.
lFuelling adaptions forced excessively rich if the EVAP canister is saturated and the purge valve is stuck open.
lSaturation of the EVAP canister if the purge valve is stuck closed.
To maintain driveability and effective emission control, EVAP canister purging must be closely controlled by the
engine management ECM, as a 1% concentration of fuel vapour from the EVAP canister in the air intake may shift
the air:fuel ratio by as much as 20%. The ECM must purge the fuel vapour from the EVAP canister at regular intervals
as its storage capacity is limited and an excessive build up of evaporated fuel pressure in the system could increase
the likelihood of vapour leaks. Canister purging is cycled with the fuelling adaptation as both cannot be active at the
same time. The ECM alters the PWM signal to the purge valve to control the rate of purging of the canister to maintain
the correct stoichiometric air:fuel mixture for the engine.
Fuel leak detection system (vacuum type) – NAS only
The advanced evaporative loss control system used on NAS vehicles is similar to the standard system, but also
includes a CVS valve and fuel tank pressure sensor and is capable of detecting holes in the fuel evaporative system
down to 1 mm (0.04 in.). The test is carried out in three parts. First the purge valve and the canister vent solenoid
valve closes off the storage system and the vent pressure increases due to the fuel vapour pressure level in the tank.
If the pressure level is greater than the acceptable limit, the test will abort because a false leak test response will
result. In part two of the test, the purge valve is opened and the fuel tank pressure will decrease due to the depression
from the intake manifold, evident at the purge port of the EVAP canister during purge operation. In part three of the
test, the leak measurement test is performed. The pressure response of the tests determines the level of leak, and if
this is greater than the acceptable limit on two consecutive tests, the ECM stores the fault in diagnostic memory and
the MIL light on the instrument pack is illuminated. The test is only carried out at engine idle with the vehicle stationary,
and a delay of 15 minutes after engine start is imposed before diagnosis is allowed to commence.
Page 377 of 1672
EMISSION CONTROL - V8
17-2-40 DESCRIPTION AND OPERATION
EVAP system, leak detection diagnostic (vacuum type)
The EVAP system leak detection is performed as follows:
1The ECM checks that the signal from the fuel tank pressure sensor is within the expected range. If the signal is
not within range, the leakage test will be cancelled.
2Next the purge valve is held closed and the canister vent solenoid (CVS) valve is opened to atmosphere. If the
ECM detects a rise in pressure with the valves in this condition, it indicates there is a blockage in the fuel
evaporation line between the CVS valve and the EVAP canister, or that the CVS valve is stuck in the closed
position and thus preventing normalisation of pressure in the fuel evaporation system. In this instance, the
leakage test will be cancelled.
3The CVS valve and the purge valve are both held in the closed position while the ECM checks the fuel tank
pressure sensor. If the fuel tank pressure sensor detects a decline in pressure, it indicates that the purge valve
is not closing properly and vapour is leaking past the valve seat face under the influence of the intake manifold
depression. In this instance, the leakage test will be cancelled.
4If the preliminary checks are satisfactory, a compensation measurement is determined next. Variations in fuel
level occur within the fuel tank, which will influence the pressure signal detected by the fuel tank pressure
sensor. The pressure detected will also be influenced by the rate of change in the fuel tank pressure, caused by
the rate of fuel evaporation which itself is dependent on the ambient temperature conditions. Because of these
variations, it is necessary for the ECM to evaluate the conditions prevailing at a particular instance when testing,
to ensure that the corresponding compensation factor is included in its calculations.
The CVS valve and purge valves are both closed while the ECM checks the signal from the fuel tank pressure
sensor. The rise in fuel pressure detected over a defined period is used to determine the rate of fuel evaporation
and the consequent compensation factor necessary.
5With the CVS valve still closed, the purge valve is opened. The inlet manifold depression present while the purge
valve is open, decreases EVAP system pressure and sets up a small vacuum in the fuel tank. The fuel tank
pressure sensor is monitored by the ECM and if the vacuum gradient does not increase as expected, a large
system leak is assumed by the ECM (e.g. missing or leaking fuel filler cap) and the diagnostic test is terminated.
If the EVAP canister is heavily loaded with hydrocarbons, purging may cause the air:fuel mixture to become
excessively rich, resulting in the upstream oxygen sensors requesting a leaner mix from the ECM to bring the
mixture back to the stoichiometric ideal. This may cause instability in the engine idle speed and consequently
the diagnostic test will have to be abandoned. The ECM checks the status of the upstream oxygen sensors
during the remainder of the diagnostic, to ensure the air:fuel mixture does not adversely affect the engine idle
speed.
6When the fuel tank pressure sensor detects that the required vacuum has been reached (-800 Pa), the purge
valve is closed and the EVAP system is sealed. The ECM then checks the change in the fuel tank pressure
sensor signal (diminishing vacuum) over a period of time, and if it is greater than expected (after taking into
consideration the compensation factor due to fuel evaporation within the tank, determined earlier in the
diagnostic), a leak in the EVAP system is assumed. If the condition remains, the MIL warning light will be turned
on after two drive cycles.
The decrease in vacuum pressure over the defined period must be large enough to correspond to a hole
equivalent to 1 mm (0.04 in.) diameter or greater, to be considered significant enough to warrant the activation
of an emissions system failure warning.
The diagnostic test is repeated at regular intervals during the drive cycle, when the engine is at idle condition. The
diagnostic test will not be able to be performed under the following conditions:
lDuring EVAP canister purging
lDuring fuelling adaption
lIf excess slosh in the fuel tank is detected (excess fuel vapour will be generated, invalidating the result)
Page 378 of 1672
EMISSION CONTROL - V8
DESCRIPTION AND OPERATION 17-2-41
Following the test, the system returns to normal purge operation after the canister vent solenoid opens. Possible
reasons for an EVAP system leak test failure are listed below:
lFuel filler not tightened or cap missing.
lSensor or actuator open circuit.
lShort circuit to vehicle supply or ground.
lEither purge or CVS valve stuck open.
lEither purge or CVS valve stuck shut or blocked pipe.
lPiping broken or not connected.
lLoose or leaking connection.
If the piping is broken forward of the purge valve or is not connected, the engine may run rough and fuelling adaptions
will drift. The fault will not be detected by the leak detection diagnostic, but it will be determined by the engine
management ECM through the fuelling adaption diagnostics.
The evaluation of leakage is dependent on the differential pressure between the fuel tank and ambient atmospheric
pressure, the diagnostic is disabled above altitudes of 9500 ft. (2800 m) to avoid false detection of fuel leaks due to
the change in atmospheric pressure at altitude.
Fuel leak detection system (positive pressure leak detection type) – NAS only
The EVAP system with positive pressure leak detection capability used on NAS vehicles is similar to the standard
system, but also includes a fuel evaporation leak detection pump with integral solenoid valve. It is capable of detecting
holes in the EVAP system down to 0.5 mm (0.02 in.). The test is carried out at the end of a drive cycle, when the
vehicle is stationary and the ignition switch has been turned off. The ECM maintains an earth supply to the Main relay
to hold it on, so that power can be supplied to the leak detection pump.
First a reference measurement is established by passing the pressurised air through a by-pass circuit containing a
fixed sized restriction. The restriction assimilates a 0.5 mm (0.02 in) hole and the current drawn by the pump motor
during this procedure is recorded for comparison against the value to be obtained in the system test. The purge valve
is held closed, and the reversing valve in the leak detection pump module is not energised while the leak detection
pump is switched on. The pressurised air from the leak detection pump is forced through an orifice while the current
drawn by the pump motor is monitored.
Next the EVAP system diagnostic is performed; the solenoid valve is energised so that it closes off the EVAP system's
vent line to atmosphere, and opens a path for the pressurised air from the leak detection pump to be applied to the
closed EVAP system.
The current drawn by the leak detection pump is monitored and checked against that obtained during the reference
measurement. If the current is less than the reference value, this infers there is a hole in the EVAP system greater
than 0.5 mm (0.02 in) which is allowing the positive air pressure to leak out. If the current drawn by the pump motor
is greater than the value obtained during the reference check, the system is sealed and free from leaks. If an EVAP
system leak is detected, the ECM stores the fault in diagnostic memory and the MIL light on the instrument pack is
illuminated.
On NAS vehicles, the ECM works on a 2 trip cycle before illuminating the MIL. On EU-3 vehicles, the ECM works on
a 3 trip cycle before illuminating the MIL.
Following the test, the solenoid valve is opened to normalise the EVAP system pressure and the system returns to
normal purge operation at the start of the next drive cycle. Possible reasons for an EVAP system leak test failure are
listed below:
lFuel filler not tightened or cap missing.
lSensor or actuator open circuit.
lShort circuit to vehicle supply or ground.
lEither purge or solenoid valve stuck open.
lEither purge or solenoid valve stuck shut.
lBlocked pipe or air filter.
lPiping broken or not connected.
lLoose or leaking connection.
If the piping is broken forward of the purge valve or is not connected, the engine may run rough and fuelling adaptions
will drift. The fault will not be detected by the leak detection test, but will be determined by the engine management
ECM through the fuelling adaption diagnostics. This test can be run from TestBook.
Page 402 of 1672
ENGINE MANAGEMENT SYSTEM - TD5
DESCRIPTION AND OPERATION 18-1-9
Connector C0658
Pin No. Input/Output Function Signal type Value Interfaces
B1 Input Earth 1 0 volts 0 volts
B2 Input Earth 4 0 volts 0 volts
B3 Input Supply battery voltage 12 volts 12 volts
B4 Output Cooling fan relay Switch 12-0 volts A/C ECU
B5 Output Fuel pump relay Switch 12-0 volts
B6 Output MIL Switch 12-0 volts Instruments
B7 Output Temperature gauge Digital 0-12 volts Instruments
B8 Not used
B9 Input A/C clutch request Switch 12-0 volts A/C ECU
B10 Input Normally closed brake
switchSwitch 12-0 volts
B11 Input Cruise control SET+ switch Switch 12-0 volts
B12 Input TP sensor 1 Analogue 0- 5 volts
B13 Input Vehicle speed Digital 0-12 volts
B14 Input TP sensor supply 5 volts 5 volts
B15 Input Cruise control master switch Switch 12-0 volts
B16 Input Normally open brake switch Switch 0-12 volts
B17 Input Cruise control RES switch Switch 12-0 volts
B18 Input/Output Serial communication link Digital 0-12 volts All ECU's
B19 Output Tachometer engine speed Digital 0-12 volts Instrument
Cluster
B20 Not used
B21 Output Main relay Switch 0-12 volts
B22 Input Supply battery voltage 12 volts 12 volts
B23 Input A/C fan request Switch 12-0 volts
B24 Input Earth 3 0 volts 0 volt
B25 Input Earth 2 0 volts 0 volts
B26 Input TP sensor earth 0 volts 0 volts
B27 Input Supply 2 12 volts 12 volts
B28 Not used
B29 Output A/C relay Switch 12-0 volts
B30 Output Glow plug warning light Switch 12-0 volts Instrument
Cluster
B31 Not used
B32 Output ABS digital 0-5 volts SLABS
B33 Input Ignition Switch 0-12 volts
B34 Input Security code digital 0-5 volts
B35 Input Clutch switch Switch 12-0 volts
B36 Input TP sensor 2 Analogue 5-0 volts
Page 412 of 1672
ENGINE MANAGEMENT SYSTEM - TD5
DESCRIPTION AND OPERATION 18-1-19
Throttle Position (TP) sensor – From VIN 297137
Discovery Series II vehicles from VIN 297137 use three track thick film potentiometers. No idle speed sender switch
is used on this type of sensor because the ECM can compare the two or three sets of signals to implement idle speed
control and over-run fuel shut-off. The two potentiometers are known as track 1 and 2 potentiometers. The track 3
potentiometer on later models is used to improve the resolution of the pedal. The ECM provides a 5V supply and
receives a signal from each of the potentiometer tracks.
a = Track 1
b = Track 2
c = Track 3
d = Voltage
e = Pedal angle (degrees)
f = Wide open throttle stop tolerance band
g = Not applicable for Discovery Series II.
With reference to the above graph, at idle (throttle released), track 2 returns a signal of 4.2V to the ECM and track 1
returns a signal of 0.8V. The ECM calculates the sum of these two figures which totals 5.0V.
At wide open throttle, track 2 returns a signal of 1.1V and track 1 returns a signal of 3.9V to the ECM. The ECM
calculates the sum of these two figures which totals 5.0V. The ECM uses this strategy to error check the TP sensor
signal and ensure that the requested throttle position is applied. The third potentiometer track measures the tolerance
of tracks 1 and 2 and provides an improved functionality check of the pedal angle.
NOTE: Three track TP sensors cannot be fitted as replacements on vehicles previously fitted with two track TP
sensors. Replacement ECM's are configured for two track TP sensors and can be fitted to all Td5 models. When
replacement ECM's are fitted to vehicles using three track TP sensors, TestBook or T4 must be used to configure the
ECM for three track TP sensor use.
If the TP sensor fails, the ECM will illuminate the MIL and the engine will operate at normal idle speed only.
Page 465 of 1672
ENGINE MANAGEMENT SYSTEM - V8
18-2-8 DESCRIPTION AND OPERATION
Input/Output
The ECM has various sensors fitted to the engine to allow it to monitor engine condition. The ECM processes these
signals and decides what actions to carry out to maintain optimum engine operation by comparing the information
from these signals to mapped data within its memory.
Connector 1 (C0634): This connector contains 9 pins and is used primarily for ECM power input and earth. The ECM
requires a permanent battery supply, if this permanent feed is lost i.e. the battery discharges or is disconnected the
ECM will lose its adapted values and its Diagnostic Trouble Codes (DTC). These adapted values are a vital part of
the engine management's rolling adaptive strategy. Without an adaptive strategy, driveability, performance, emission
control, and fuel consumption are adversely affected. The ECM can be damaged by high voltage inputs, so care must
be taken when removing and replacing the ECM.
Pin out details connector C0634
Connector 2 (C0635): This connector contains 24 pins and is primarily used for Heated Oxygen Sensors (HO
2S)
control and earth. The HO
2S sensors require a heater circuit to assist in heating the tip of the sensors to enable closed
loop fuelling to be implemented quickly after cold starting.
Pin out details connector C0635
Pin No. Function Signal type Reading
1 Ignition position II Input 12 V
2 Not used - -
3 Not used - -
4 Chassis earth Earth 0V
5 Fuel injectors earth Earth 0V
6 Power stage earth Earth 0V
7 Permanent battery supply Input battery supply 12V
8 Switched relay positive Input switched 0-12V
9 Not used - -
Pin No. Function Signal type Reading
1HO
2S heater RH bank - downstream Output PWM 12-0V
2 Not used - -
3 Not used - -
4 Not used - -
5 Thermostat monitoring sensor Earth 0V
6 Not used - -
7HO
2S heater LH bank - downstream Output PWM 12-0V
8HO
2S sensor RH bank - downstream Earth/ Signal 0V
9HO
2S sensor LH bank - upstream Earth/ Signal 0V
10 HO
2S sensor RH bank - upstream Earth/ Signal 0V
11 HO
2S sensor LH bank - downstream Earth/ Signal 0V
12 Not used - -
13 HO
2S heater RH bank - upstream Output PWM 12-0V
14 HO
2S sensor RH bank - downstream Input/ Signal Analogue 0-5V
15 HO
2S sensor LH bank - upstream Input/ Signal Analogue 0-5V
16 HO
2S sensor RH bank - upstream Input/ Signal Analogue 0-5V
17 HO
2S sensor LH bank - downstream Input/ Signal Analogue 0-5V
18 Fuel pump relay Output Switch to earth
19 HO
2S heater LH bank - upstream Output PWM 12-0V
20 Not used - -
21 Thermostat monitoring sensor Signal Analogue 0-5V
22 Not used - -
23 Main relay Output Switch to earth
24 EVAP system leak detection pump motor (NAS
vehicles with positive pressure type, EVAP system
leak detection capability only)Output Switch to earth
Page 466 of 1672
ENGINE MANAGEMENT SYSTEM - V8
DESCRIPTION AND OPERATION 18-2-9
Connector 3 (C0636): This connector contains 52 pins and is used for most sensor and actuator inputs and outputs.
Sensor and actuator control is vital to ensure that the ECM maintains adaptive strategy
Pin out details connector C0636
Pin No. Function Signal type Reading
1 Injector cylinder number 2 Output Switch to earth
2 Injector cylinder number 5 Output Switch to earth
3 Purge valve Output, signal PWM 12-0V
4 SAI vacuum solenoid valve (NAS vehicles from
2000MY only)Output Switch to earth
5 Not used - -
6 Fuel tank pressure sensor (NAS vehicles with
vacuum type, EVAP system leak detection
only)Earth 0V
7 MAF sensor 5V supply Output, reference 5V
8 Not used - -
9 MAF sensor earth Earth 0V
10 TP sensor 5V supply Output, reference 5V
11 Not used - -
12 Not used - -
13 Not used - -
14 Injector cylinder number 7 Output Switch to earth
15 Injector cylinder number 6 Output Switch to earth
16 SAI pump relay (NAS vehicles from 2000MY
only)Output Switch to earth
17 CMP sensor Earth 0V
18 Low range switch (manual transmission only) Input, signal Active low
19 Not used - -
20 CMP signal Input, signal Digital switch 0-12V
21 ECT sensor Earth 0V
22 Coolant temperature signal Input, signal Analogue 0-5V
23 MAF sensor signal Input, signal Analogue 0-5V
24 TP sensor signal Input, signal Analogue 0-5V
25 TP sensor earth Earth 0V
26 Not used - -
27 Injector cylinder number 3 Output Switch to earth
28 Injector cylinder number 8 Output Switch to earth
29 Hill decent control output Output, signal PWM 0-12V
30 EVAP canister vent solenoid (CVS) valve (NAS
vehicles with vacuum type, EVAP system leak
detection only)Output Switch to earth
30 Leak detection pump solenoid (NAS vehicles
with positive pressure type, EVAP system leak
detection only)Output Switch to earth
31 A/C condenser fan Output Switch to earth
32 CKP sensor signal Input, signal Analogue, 0-300V peak
33 Not used - -
34 IAT sensor signal Input, signal Analogue 0-5V
35 KS, RH bank earth Earth 0V
36 KS, RH bank signal Input, signal Analogue
37 Not used - -
38 Not used - -
39 Not used - -
40 Injector cylinder number 4 Output Switch to earth
41 Injector cylinder number 1 Output Switch to earth
Page 467 of 1672
ENGINE MANAGEMENT SYSTEM - V8
18-2-10 DESCRIPTION AND OPERATION
Connector 4 (C0637): This connector contains 40 pins and facilitates use of TestBook via the Diagnostic connector.
Also contained in this connector is the Malfunction Indicator Lamp (MIL), this instrument panel lamp informs the driver
of concerns within the engine management system.
Pin out details connector C0637
42 Idle air control valve open Output, signal PWM 12-0V
43 Idle air control valve close Output, signal PWM 12-0V
44 ECT sensor signal Output, signal PWM 0-12V
45 CKP sensor earth screen Earth 0V
46 CKP sensor signal Earth reference 0V
47 Not used - -
48 KS, LH bank earth Earth 0V
49 KS, LH bank signal Input, signal Analogue
50 Not used - -
51 Not used - -
52 Not used - -
Pin No. Function Signal type Reading
1 Not used - -
2 Not used - -
3 Not used - -
4 Not used - -
5 Not used - -
6 Not used - -
7 Not used - -
8 Low fuel level Input, signal Active high
9 Fuel tank pressure sensor (NAS vehicles with
vacuum type, EVAP system leak detection
capability only)Output, reference 5V
10 Not used - -
11 Not used - -
12 Analogue fuel level (NAS vehicles with positive
pressure type, EVAP system leak detection only)Input, signal 0-5V
13 Not used - -
14 Fuel tank pressure sensor (NAS vehicles with
vacuum type, EVAP system leak detection
capability only)Input, signal Analogue 0-5V
15 Not used - -
16 ATC compressor request Input, signal Active low
17 Engine speed output Output, signal PWM 0-5V
18 Not used - -
19 Not used - -
20 Malfunction indicator lamp 'ON' Output Switched earth
21 Not used - -
22 Vehicle speed signal (VSS) Input, signal PWM 0-12V
23 Not used - -
24 Not used - -
25 Not used - -
26 Not used - -
27 Not used - -
28 Not used - -
29 ATC compressor relay Output Switched earth
30 Not used - - Pin No. Function Signal type Reading
Page 469 of 1672
ENGINE MANAGEMENT SYSTEM - V8
18-2-12 DESCRIPTION AND OPERATION
Connector 5 (C0638): This connector contains 9 pins and is used to control the ignition system. The ignition coils are
supplied with power and a switching earth completes the circuit.
Pin out details connector C0638
Crankshaft speed and Position (CKP) sensor (C0168)
The CKP sensor is located towards the rear of the engine below cylinder number 7, with its tip adjacent to the outer
circumference of the flywheel. The CKP sensor is the most important sensor on the vehicle and without its signal the
engine will not run. The signal produced by the CKP sensor allows the ECM to determine crankshaft angle and speed
of rotation. The ECM uses this information to calculate ignition timing and fuel injection timing.
The CKP sensor works as a variable reluctance sensor. It uses an electromagnet and a reluctor ring to generate a
signal. As the reluctor ring passes the tip of the CKP sensor the magnetic field produced by the sensor is cut and then
re-instated. The ECM measures the signal as an ac voltage.
The output voltage varies in proportion to engine speed. The reluctor ring has a set tooth pattern, 60 teeth are spaced
at 6
° intervals and are 3° wide, two teeth are removed to provide a reference mark at 60° BTDC for number 1 cylinder.
There is no back up strategy or limp home facility if this sensor fails, the engine does not run.
Pin No. Function Signal type Reading
1 Not used - -
2 Ignition , Cylinders 2 and 3 Output Switch to earth
3 Not used - -
4 Not used - -
5 Ignition coil earth Earth 0V
6 Ignition , Cylinders 1 and 6 Output Switch to earth
7 Ignition , Cylinders 4 and 7 Output Switch to earth
8 Ignition , Cylinders 5 and 8 Output Switch to earth
9 Not used - -
Page 476 of 1672
ENGINE MANAGEMENT SYSTEM - V8
DESCRIPTION AND OPERATION 18-2-19
Input/Output
The ECM provides the thermostat monitoring sensor with a 5 volt reference via pin 21 of connector C0635 of the ECM,
and an earth via pin 5 of connector C0635 of the ECM.
There are three types of thermostat monitoring sensor diagnostic checks:
lSensor signal is above maximum threshold. For the ECM to register this as a fault, and illuminate the MIL, the
temperature registered by the thermostat monitoring sensor must be above 140
°C (284 °F) for more than 1
second.
lSensor signal is below minimum threshold. For the ECM to register this as a fault, and illuminate the MIL, the
temperature registered by the thermostat monitoring sensor must be below -33
°C (-27 °F) for more than 1
second, while the inlet air temperature reading is greater than -32
°C (-25 °F).
lSignal difference between ECT sensor and thermostat monitoring sensor is below maximum threshold. For the
ECM to register this as a fault, and illuminate the MIL, the following conditions must exist:
lNo maximum or minimum threshold signal faults exist.
lNo faults are recorded against the thermostat monitoring sensor or vehicle speed signal.
lEngine not in idle speed control.
lFuel cut-off not active.
lEngine speed is greater than 400 rpm.
lRoad speed is greater than 0 mph.
lIntegrated mass air flow from engine start to fuel cut-off is greater than set value (between 3 kg and 10 kg
dependent upon engine coolant temperature at engine start).
lEngine coolant temperature at engine start is between 9
°C and 39 °C (48 °F and 102 °F).
lHigh range is selected.
lDelay time before thermostat monitoring is enabled is between set limits (between 50 and 500 seconds
dependent upon engine coolant temperature at engine start).
lEngine coolant temperature is greater than 90
°C (194 °F).
lThe difference between the ECT sensor reading and the thermostat monitoring sensor reading is less than
39
°C (102 °F).