Land Rover Lesson 2 Auto Trans Coolingine Rover Manual

							Voltage (Volts)Resistance (Kohms)Temperature (Degrees
Celsius)
0.642.990
0.492.08100
0.381.56110
0.291.19120
0.220.918130
0.170.673140
0.140.563150
If the ECT sensor fails, the following symptoms may
be observed:
•Difficult cold start.
•Difficult hot start.
•Engine performance compromised.
•Temperature gauge inoperative or inaccurate reading.
In the event of ECT sensor signal failure, the ECM
applies a default value of 80°Celsius (176°F) coolant
temperature for fuelling purposes. The ECM will also
permanently operate the cooling fan at all times when
the ignition is switched on, to protect the engine from
overheating.
ENGINE OIL TEMPERATURE
SENSOR
The oil temperature sensor is located in the engine sump.
The temperature sensor is a NTC type which operates
in the -30 Degrees Celsius to +150 Degrees Celsius
temperature range.
Oil Temperature Sensor Response
Resistance OhmsTemperature Degrees
Celsius
62060
25590
117120
60150
FUEL RAIL TEMPERATURE
SENSOR
The fuel rail temperature sensor is located on the LP
return line.
The sensor is an NTC sensor which is connected to the
ECM by two wires. The ECM fuel temperature sensor
circuit consists of an internal voltage divider circuit
which incorporates an NTC thermistor. As the fuel
temperature rises the resistance through the sensor
decreases. The output from the sensor is the change in
voltage as the thermistor allows more current to pass to
earth relative to the temperature of the fuel.
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							The ECM monitors the fuel temperature constantly. If
the fuel temperature exceeds 85°Celsius (185°F), the
ECM invokes an engine derate strategy. This reduces
the amount of fuel delivered to the injectors in order to
allow the fuel to cool. When this occurs, the driver may
notice a loss of performance.
Further fuel cooling is available by a bi-metallic valve
diverting fuel through the fuel cooler when the fuel
reaches a predetermined temperature. In hot climate
markets, an electrically operated cooling fan is
positioned in the air intake ducting to the fuel cooler.
This is controlled by a thermostatic switch, which
switches the fan on and off when the fuel reaches a
predetermined temperature.
The wires to the fuel sensor are monitored by the ECM
for short and open circuit. The ECM also monitors the
5V supply. If a failure occurs a fault is recorded in the
ECM memory and the ECM uses a default fuel pressure
value.
If the ECM registers an out of range deviation between
the pressure signal from the sensor and the
pre-programmed set point a fault is stored in the ECM
memory. Depending on the extent of the deviation, the
ECM will reduce the injection quantity, stop the engine
immediately or prevent further engine starting.
BRAKE LIGHT SWITCH
The brake switch is located on the brake pedal and is
operated by the brake pedal. The switch has a normally
open circuit switch which closes the circuit when the
driver has applied the brakes. The switch is connected
directly to the ECM and the ECM also receives a brake
light signal on the CAN bus from the ABS module.
The ECM uses the brake signal for the following:
To limit fuelling during braking
To inhibit/cancel Speed control if the brakes are applied.
In the event of a brake switch failure, the following
symptoms may be observed:
Speed control inactive
Increased fuel consumption.
GLOW PLUGS
Three glow plugs are located in each of the cylinder
heads, on the inlet side. The glow plugs and the glow
plug relay are a vital part of the engine starting strategy.
The glow plugs heat the air inside the cylinder during
cold starts to assist combustion. The use of glow plugs
helps reduce the amount of additional fuel required on
start-up, and consequently reduces the emission of black
smoke. The use of glow plugs also reduces the amount
of injection advance required, which reduces engine
noise, particularly when idling with a cold engine.
There are three phases of glow plug activity:
•Pre-heat
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							•During crank
•Post heat
The main part of the glow plug is a tubular heating
element which protrudes into the combustion chamber
of the engine. The heating element contains a spiral
filament encased in magnesium oxide powder. At the
tip of the tubular heating element is the heater coil.
Behind the heater coil, and connected in series, is a
control coil. The control coil regulates the heater coil
to ensure that it does not overheat.
Pre-heat is the length of time the glow plugs operate
prior to engine cranking. The ECM controls the pre-heat
time based on ECT sensor output and battery voltage.
If the ECT sensor fails, the ECM will use the IAT sensor
value as a default value. The pre-heat duration is
extended if the coolant temperature is low and the
battery is not fully charged.
Post heat is the length of time the glow plugs operate
after the engine starts. The ECM controls the post
heating time based on ECT sensor output. The post heat
phase reduces engine noise, improves idle quality and
reduces hydrocarbon emissions.
When the ignition is switched on to position II, the glow
plug warning lamp illuminates and the instrument cluster
displays PREHEATING in the message centre. The
glow-lamp is activated separately from the glow-plugs,
so is not illuminated during or after start. The plugs can
still be ON when the lamp is off in these two phases.
In the event of glow plug failure, the engine may be
difficult to start and excessive smoke emissions may be
observed after starting.
The glow plug warning lamp also serves a second
function within the EDC system. If a major EDC system
fault occurs, the glow plug warning lamp will be
illuminated permanently and a message generated in
the instrument cluster. The driver must seek attention
to the engine management system at a Land Rover dealer
as soon as possible.
INTAKE AIR TEMPERATURE
(BOOST AIR TEMPERATURE)
SENSOR
The IAT (intake air temperature) is located in the rear
of the intake chamber immediately preceding the electric
throttle. The sensor is used to measure the intake air
temperature from the turbo in order to calculate the
required amount of fuelling.
BOOST PRESSURE CONTROL
The Boost Pressure (BP) sensor is located post turbo
after the eclectic throttle valve. The sensor provides a
voltage signal to the ECM relative to the intake manifold
pressure. The BP sensor has a three pin connector which
is connected to the ECM and provides a 5V reference
supply from the ECM, a signal input to the ECM and a
ground for the sensor.
The BP sensor uses diaphragm transducer to measure
pressure. The ECM uses the BP sensor signal for the
following functions:
•Maintain manifold boost pressure.
•Reduce exhaust smoke emissions when driving at
high altitude.
•Control of the EGR system.
•Control of the vacuum control module.
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							If the BP sensor fails, the ECM uses a default pressure
of 1013 mbar (14 lbf/in²). In the event of a BP sensor
failure, the following symptoms may be observed:
•Altitude compensation inoperative (black smoke
emitted from the exhaust).
•Active boost control inoperative.
Boost control is achieved by the use of a direct drive
electric actuator. The actuator is attached to the side of
the turbo unit and is connected with the control
mechanism via a linkage. The electric actuator works
on the torque motor principal and has integrated control
module.
The electric actuator moves the control vanes through
an 60 degree stroke and has the capability to learn its
own maximum stroke positions. The electric actuator
is controlled via PWM signals from the ECM.
FUEL RAIL PRESSURE CONTROL
VALVE
Fuel volume control valve1
High pressure fuel pump2
Fuel rail pressure control valve3
The fuel rail pressure control valve is incorporated into
the high pressure fuel pump. The control valve regulates
the fuel pressure within the fuel rail and is controlled
by the ECM. The control valve is a PWM controlled
solenoid valve.
When the solenoid is de-energised, an internal spring
holds an internal valve closed. At fuel pressure of 100
bar (1450 lbf/in²) or higher, the force of the spring is
overcome, opening the valve and allowing fuel pressure
to decay into the fuel return pipe. When the pressure in
the fuel rail decays to approximately 100 bar (1450
lbf/in²) or less, the spring force overcomes the fuel
pressure and closes the valve. When the ECM energises
the solenoid, the valve is closed allowing the fuel
pressure to build. The pressure in the fuel rail in this
condition can reach approximately 1300 bar (18854
lbf/in²).
The ECM controls the fuel rail pressure by operating
the control valve solenoid using a PWM signal. By
varying the duty cycle of the PWM signal, the ECM
can accurately control the fuel rail pressure and hence
the pressure delivered to the injectors according to
engine load. This is achieved by the control valve
allowing a greater or lesser volume of fuel to pass from
the high pressure side of the pump to the un-pressurised
fuel return line, regulating the pressure on the high
pressure side.
The fuel rail pressure control valve receives a PWM
signal from the ECM of between 0 and 12V. The ECM
controls the operation of the control valve using the
following information to determine the required fuel
pressure:
•Fuel rail pressure
•Engine load
•Accelerator pedal position
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							•Engine temperature
•Engine speed.
In the event of a total failure of the fuel rail pressure
control valve, the engine will not start.
In the event of a partial failure of the fuel rail pressure
control valve, the ECM will activate the solenoid with
the minimum duty cycle which results in the injection
quantity being limited.
FUEL VOLUME CONTROL VALVE
The fuel rail volume control valve is incorporated into
the high pressure fuel pump. The VCV spills unwanted
fuel back to the tank (or LP system) or forwards it to
the PCV. This avoids unused fuel being pressurised by
the HP stage of the pump, only to be spilt back to LP
by the PCV wasting energy and heating the fuel.
INJECTORS
There are six electronic fuel injectors (one for each
cylinder) located in a central position between the four
valves of each cylinder. The ECM divides the injectors
into two banks of three with cylinders 1 to 3 being
designated bank A and cylinders 4 to 6 designated bank
B, with injector numbers 1 and 4 at the front of the
engine. Although the injectors are numbered 1-6 the
firing order determined by the ECM software is
numbered 0-5.
Injector/Cylinder Numbering
Cylinder NoInjector
10
41
22
Cylinder NoInjector
53
34
65
Each injector is supplied with pressurised fuel from the
fuel rail and delivers finely atomised fuel directly into
the combustion chambers. Each injector is individually
controlled by the ECM which operates each injector in
the firing order and controls the injector opening period
via PWM signals. Each injector receives a 12V supply
from the ECM and, using programmed injection/timing
maps and sensor signals, determines the precise pilot
and main injector timing for each cylinder. If battery
voltage falls to between 6 and 9V, fuel injector operation
is restricted, affecting emissions, engine speed range
and idle speed. In the event of a failure of a fuel injector,
the following symptoms may be observed:
•Engine misfire
•Idle irregular
•Reduced engine performance
•Reduced fuel economy
•Difficult starting
•Increased smoke emissions.
The ECM monitors the wires for each injector for short
circuit and open circuit, each injector and the transient
current within the ECM. If a defect is found, an error is
registered in the ECM for the injector in question.
EGR SYSTEM
The EGR system comprises:
•EGR modulator x 2
•EGR cooler x 2
•Associated connecting pipes
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							EGR
The EGR modulator and cooler are a combined unit.
The combined EGR modulator and cooler is located
under each cylinder bank, between the exhaust manifold
and the cylinder head. The cooler side of the EGR is
connected to the vehicle cooling system, via hoses. The
inlet exhaust side is connected directly into the exhaust
manifolds on each side. The exhaust gas passes through
the cooler and is expelled via the actuator and a metal
pipe into the throttle housing. The EGR modulator is a
solenoid operated valve which is controlled by the ECM.
The ECM uses the EGR modulator to control the amount
of exhaust gas being re-circulated in order to reduce
exhaust emissions and combustion noise. The EGR is
enabled when the engine is at normal operating
temperature and under cruising conditions.
The EGR modulator receives a 12V supply from the
ECM and is controlled using a PWM signal. The PWM
duty signal of the solenoid ground is varied to determine
the precise amount of exhaust gas delivered to the
cylinders.
The modulators are operated through their full range at
each engine shut down, to clear any carbon deposits that
may have built up whilst the engine was running
In the event of a failure of the EGR modulator, the EGR
function will become inoperative. The ECM can monitor
the EGR modulator solenoid for short circuits and store
fault codes in the event of failure. The modulator can
also be activated for testing using T4.
ACCELERATOR PEDAL POSITION
SENSOR (APP)
The Accelerator Pedal Position Sensor (APP) is
incorporated into the pedal assembly. The sensor is a
twin track rotary potentiometer type.
The APP sensor is located in plastic housing which is
integral with the throttle pedal. The housing is injection
moulded and provides location for the APP sensor. The
sensor is mounted externally on the housing and is
secured with two Torx screws. The external body of the
sensor has a six pin connector which accepts a connector
on the vehicle wiring harness.
The sensor has a spigot which protrudes into the housing
and provides the pivot point for the pedal mechanism.
The spigot has a slot which allows for a pin, which is
attached to the sensor potentiometers, to rotate through
approximately 90°, which relates to pedal movement.
The pedal is connected via a link to a drum, which
engages with the sensor pin, changing the linear
movement of the pedal into rotary movement of the
drum. The drum has two steel cables attached to it. The
cables are secured to two tension springs which are
secured in the opposite end of the housing. The springs
provide feel on the pedal movement and require an
effort from the driver similar to that of a cable controlled
throttle. A detente mechanism is located at the forward
end of the housing and is operated by a ball located on
the drum. At near maximum throttle pedal movement,
the ball contacts the detente mechanism. A spring in the
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							mechanism is compressed and gives the driver the
feeling of depressing a kickdown switch when full
pedal travel is achieved.
ELECTRONIC THROTTLE
The electric throttle body is located in the inlet tract
prior to where the inlet splits to divert air flow into the
two separate air intake manifolds. The electric throttle
controls the volume of air allowed into the inlet
manifold by means of a DC motor which controls a flap
in the body of the throttle. This is done in response to
inputs from the engine management system.
Just after the throttle flap the tubes from the EGR
valves/coolers are joined into the assembly.
TERRAIN RESPONSE ™
Terrain Response ™ system allows the driver to select
a program which will provide the optimum settings for
traction and performance for prevailing terrain
conditions.
As part of Terrain Response ™ there will be different
throttle pedal progression maps associated with different
Terrain Response ™ modes. The two extremes are likely
to be a sand map (quick build up of torque with pedal
travel) and grass/gravel/snow (very cautious build up
of torque).
The TdV6 implementation of throttle progression is
based on a fixed blend time. The torque will blend from
that on one map to that on the new map (for the same
pedal position) over a fixed time. This means blending
will always take the same amount of time but when the
torque change is small the torque increase over time
will be small, whilst if the torque change is greater then
the torque increase over time will be steeper. The
resulting acceleration of the vehicle will depend on the
torque difference between the two maps as well as on
the gear and range selected. The worst case blending
that could ever occur has been calibrated to match the
blend rate for petrol derivatives as closely as possible,
so as to give a transparent behaviour to customers.
CENTRAL JUNCTION BOX
The CJB initiates the power up and power down routines
within the ECM. When the ignition is turned on 12V is
applied to the Ignition Sense input. The ECM then starts
its power up routines and turns on the ECM main relay;
the main power to the ECM and its associated system
components. When the ignition is turned OFF the ECM
will maintain its powered up state for up to 20 seconds
while it initiates its power down routine and on
completion will turn off the ECM main relay.
Electronic Engine ControlsLesson 2 – Powertrain
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							GENERATOR
The generator has a multifunction voltage regulator for
use in a 14V charging system with 6÷12 zener diode
bridge rectifiers.
The ECM monitors the load on the electrical system via
PWM signal and adjusts the generator output to match
the required load. The ECM also monitors the battery
temperature to determine the generator regulator set
point. This characteristic is necessary to protect the
battery; at low temperatures battery charge acceptance
is very poor so the voltage needs to be high to maximise
any rechargeability, but at high temperatures the charge
voltage must be restricted to prevent excessive gassing
of the battery with consequent water loss.
The generator has a smart charge capability that will
reduce the electrical load on the generator reducing
torque requirements, this is implemented to utilise the
engine torque for other purposes. This is achieved by
monitoring three signals to the ECM:
•Generator sense (A sense), measures the battery
voltage at the CJB.
•Generator communication (Alt Com) communicates
desired generator voltage set point from ECM to
generator.
•Generator monitor (Alt Mon) communicates the
extent of generator current draw to ECM. This signal
also transmits faults to the ECM which will then
sends a message to the instrument cluster on the
CAN bus to illuminate the charge warning lamp.
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							Cooling System Component Layout
Heater hose, inlet and outlet1
Heater hose, inlet and outlet for vehicles with
rear heater (optional)
2
Hose, radiator to intake manifold3
Radiator top hose4
Engine Coolant Temperature (ECT) sensor5
Water pump6
Throttle body7
Inlet manifold8
Throttle body coolant hose9
Hose, engine to expansion tank10
Expansion tank11
Radiator bottom hose12
Engine oil cooler (if fitted)13
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							Hose (for vehicles without engine oil cooler)14
Hose, inlet and outlet (for vehicles with engine
oil cooler)
15
Cooling fan16
Transmission oil cooler pipes17
Radiator cowl, lower18
Radiator19
Radiator cowl, upper20
GENERAL
The cooling system employed is of the pressure relief
by-pass type, which allows coolant to circulate around
the engine and the heater circuit while the thermostat
main valve is closed. The primary function of the
cooling system is to maintain the engine within an
optimum temperature range under changing ambient
and engine operating conditions. Secondary functions
are to provide heating for the passenger compartment
and cooling for the transmission fluid and engine oil.
The cooling system comprises:
•A radiator
•A passenger compartment heater matrix
•An Engine Oil Cooler (EOC)
•A coolant pump
•A Pressure Relief Thermostat (PRT)
•An expansion tank
•A viscous fan
•Connecting hoses and pipes.
ENGINE COOLING SYSTEM
The coolant is circulated by a centrifugal pump mounted
on the front of the engine and driven by an ancillary
drive polyvee belt. The coolant pump circulates coolant
through the cylinder block and cylinder heads via a
chamber located in the vee of the engine. Having passed
through the engine the coolant returns to the thermostat
housing via the bypass pipe. Coolant also circulates
through the top hose to the heater matrix. The coolant
returns via the EOC to the engine side of the PRT.
The PRT housing contains a normal thermostat, which
is positioned such that the waxs temperature is
controlled by both the coolant from the radiator and the
bypass. This results in the thermostat being able to vary
its opening temperature dependant on ambient
conditions. The PRT also contains a sprung loaded
valve, which limits the amount flow using the bypass.
This means that the engine can run without coolant
flowing through the bypass temporarily, to improve
heater performance.
The radiator is a cross flow type with an aluminium
matrix and has a drain tap on the lower right-hand rear
face. The lower radiator mountings are located part way
up the end tanks. The mountings are fitted with rubber
bushes, which sit on the upper chassis rails. The radiator
upper is mounted by pins, which are pushed through
rubber bushes mounted in the Front End Carrier (FEC)
above the radiator. The radiator also incorporates two
connections for the transmission oil cooler pipes.
The radiator top hose is connected to the PRT by the
bypass hose and the bottom hose is directly connected
to the outlet side of the thermostat housing.
The expansion tank is fitted forward of the LH
suspension turret in the engine compartment. The
expansion tank allows for the expansion of the coolant
as the engine gets hot and also supplies the engine with
coolant as the coolant in the engine contracts. The tank
also allows any air trapped in the coolant to be removed.
The liquid cooled transmission fluid cooler is mounted
in the cold side radiator end tank. It is positioned in the
middle of the LH end tank.
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