Exhaust JAGUAR XF 2009 1.G AJ133 5.0L Engine Manual

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04/14/2009 NP10-V8JLR: AJ133 5.0-Liter DFI V8 Engine
Technical Training
Engine Control Module

Engine Management System

ENGINE CONTROL MODULE
The ECM is supplied with battery voltage from a 5A fuse and an ignition supply from the ECM relays through\
a 15A
fuse, both located in the CJB. A regulator located within the ECM supplies a 5V current to internal compone\
nts such
as the microprocessor unit. Other components or functions requiring full\
battery voltage are controlled by external
relays or internal switching modules.
The microprocessor within the ECM receives signals from different components and control modules and uses a pro-
gram within the ECM software to interpret the signal information and issue signals which relate t\
o how the engine
components and functions should be controlled. The ECM communicates with other control modules via bidirectional
Controller Area Network (CAN) communication interfaces.
The ECM uses the following inputs and outputs:
Inputs
• Camshaft position (CMP) sensor
• Crankshaft position (CKP) sensor
• Fuel rail high-pressure sensor
• Mass air flow (MAF) sensors (2)
• Knock sensors (4)
• Engine coolant temperature (ECT) sensor
• Manifold absolute pressure (MAP) sensor
• Electronic throttle position sensor
• Accelerator pedal position (APP) sensor
• Cooling fan speed
• Upstream Universal Heated Exhaust Gas Oxygen (UHEGO) sensors (2)
• Brake switch
• Speed control cancel/suspend switch
• Intake air temperature (IAT) sensor (integrated into the MAF) (2)
• Ambient air temperature (AAT) sensor
• Engine oil level and temperature sensor
• Temperature and manifold absolute pressure (TMAP) sensor (SC only)
Outputs

• Throttle Actuator
• Coil-on-plug (COP) ignition coils (8)
• Upstream Universal Heated Exhaust Gas Oxygen (UHEGO) sensors (2)
• Downstream Heated Oxygen Sensors (HO2S) (2)
• Direct injection fuel injectors (8)
• Variable camshaft timing (VCT) solenoids (4)
• Camshaft profile switching (CPS) solenoids (2)
• Intake manifold tuning solenoid
• Carbon canister purge valve
• Fuel pump relay
• Starter relay
• A/C condenser fan relay
• ECM main relay viscous fan control
• Generator control
• Air flap solenoid (SC only)
• Pump control diagnostics
• Diagnostic Monitoring of Tank Leakage (DMTL)

Technical Training
NP10-V8JLR: AJ133 5.0-Liter DFI V8 Engine 04/14/2009
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Engine Management System

Mass Air Flow Sensor

MASS AIR FLOW SENSOR
Mass air flow is determined by the cooling effect of
intake air passing over a ‘hot film’ element contained
within the device. The higher the air flow the greater the
cooling effect and the lower the electrical resistance of
the ‘hot film’ element. The ECM then uses this analog
signal from the mass air flow (MAF) sensor to calculate
the air mass flowing into the engine.
The measured air mass flow is used in determining the
fuel quantity to be injected in order to maintain the sto-
ichiometric air/fuel mixture required for correct opera-
tion of the engine and exhaust catalysts. Should the
device fail, there is a software backup strategy that will
be activated once a fault has been logged.
The intake air temperature (IAT) sensor is integrated into
the MAF sensor. The IAT sensor is an NTC thermistor,
meaning that the sensor resistance decreases as the sen-
sor temperature increases.
The sensor forms part of a voltage divider chain with an
additional resistor in the ECM. The voltage from this device
changes as the sensor resistance changes, thus relating the
air temperature to the voltage measured by the ECM.
Because the engine requires a twin air intake induction
system, there are two MAF sensors per vehicle.
Safety Precautions CAUTIONS:
• Component should not be dropped or han-dled roughly.
• Ensure that no contamination enters the device.
• Some terminals in MAF and connector are gold-plated for corrosion resistance – DO
NOT probe.
Failure Modes
• Sensor open circuit
• Short circuit to battery voltage or ground
• Contaminated/damaged sensor element
• Air leak after MAF sensor
• Intake air restricted
• Resistance in the harness, causing signal offset
• Damaged sensor element
Failure Symptoms
• During driving the engine rpm might dip (before recovering)
• Difficulty in starting or start/stall
• Poor throttle response/engine performance
• Emissions incorrect
• Lambda control and idle speed control halted
• MAF signal offset
NP10V8102
SpecificationFunction
Supply Voltage 8 – 14V
(rated supply voltage: 14V)
Pin A Output (Vg)
Pin B Ground for Output (Vg)
Pin C Power Source
Pin D IAT Sensor Ground
Pin E IAT Sensor Output

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Heated Oxygen SensorsEngine Management System
HEATED OXYGEN SENSORS
The heated oxygen sensors monitor the level of oxygen
in the exhaust gases and are used to control the fuel/air
mixture. Positioning the sensors in the stream of exhaust
gasses from each bank enables the ECM to control the
fuel metering on each bank independently of the other,
allowing much closer control of the air/fuel ratio and cat-
alyst conversion efficiency.
There are four heated oxygen sensors per engine:
• One upstream Universal Heated Exhaust Gas Oxy-
gen (UHEGO) sensor per bank
• One downstream Heated Oxygen Sensor (HO2S) per bank.
NP10V8106
UPS TREAM
DOWNSTREAM
GAS FLOW
UPSTREAM
UHEGO
1st BRICK 2nd BRICK DOWNS
TREAM
HO2S
NP10V8107

Technical TrainingNP10-V8JLR: AJ133 5.0-Liter DFI V8 Engine04/14/20093-23
Engine Management SystemHeated Oxygen Sensors
Upstream Universal Heated Exhaust Gas Oxygen Sensors
In order to improve the control of the air : fuel ratio
(AFR) under varying engine conditions, a linear or ‘uni-
versal’ heated exhaust gas oxygen (UHEGO) sensor is
used in the upstream location. The UHEGO has a vary-
ing current response to changes in the exhaust gas oxy-
gen content.
The AFR can be maintained more precisely within a
range from approximately 12:1 to 18:1, not just stoichio-
metric. Voltage is maintained at approximately 450 mV
by applying a current.
The current required to maintain the constant voltage is
directly proportional to the AFR. A higher current indi-
cates a leaner condition; a lower current indicates a
richer condition. The current varies with the temperature
of the sensor and is therefore difficult to measure for
technician diagnostic purposes.
The upstream UHEGO sensors need to operate at high
temperatures – 750°C (1,382°F) – in order to function
correctly. To achieve this, the sensors are fitted with
heater elements that are controlled by a PWM signal
from the ECM.
The heater elements are operated immediately following
engine start and also during low load conditions when
the temperature of the exhaust gases is insufficient to
maintain the required sensor temperatures.A non-functioning heater delays the sensor’s readiness
for closed loop control and influences emissions. The
PWM duty cycle is carefully controlled to reduce ther-
mal shock risk to cold sensors.
The upstream UHEGO sensors are mounted to the
engine on the exhaust manifolds, in the mating flange to
the exhaust pipes. There is one sensor per bank. The sen-
sors are fitted during engine assembly.
Upstream UHEGO Output
NP10V8108
+10 mA
NOMINAL APPLIED CURRENT
-10 mA
AFR 12:1
APPLIED CURRENT(APPROXIMATE)
AFR 18:1λ = 1

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Heated Oxygen SensorsEngine Management System
Downstream Heated Oxygen Sensors
The latest switching downstream exhaust sensors are
precise-control heated oxygen sensors (HO2S). These
sensors have a tighter lean/rich tolerance compared to
previous HO2S. The only visible distinction between the
current and previous HO2S is the part number.
The downstream HO2S uses smaller elements in its con-
struction to enable quicker heat-up times to control fuel
metering at lower temperatures (emissions).
The primary function of the downstream HO2S is to
ensure correct operation of the three way catalyst.
The downstream HO2S uses Zirconium technology that
produces an output voltage dependant upon the ratio of
exhaust gas oxygen to the ambient oxygen. The device
contains a Galvanic cell surrounded by gas-permeable
ceramic, the voltage of which depends upon the level of
O2 diffusing through.
Nominal output voltage of the device for lambda = 1 is
300 – 500mV. As the fuel mixture becomes richer (<1)
the voltage tends towards 900mV and as it becomes
leaner (lambda > 1) the voltage tends towards 0 volts. The downstream HO2S are mounted in the exhaust sys-
tem part way in the rear of the catalyst.
Downstream HO2S Output
NP10V8115
V
λ = 1
4.5V

Technical TrainingNP10-V8JLR: AJ133 5.0-Liter DFI V8 Engine04/14/20093-25
Engine Management SystemHeated Oxygen Sensors
Safety Precautions
WARNINGS:
• Anti-seize compound used on service sensor threads may be a health hazard. Avoid skin
contact.
• Exhaust system components, catalysts in particular, operate at high temperatures and
remain hot for a long time after operation.
CAUTIONS:
• Oxygen sensors must be treated with the utmost care before and during the fitting
process. The sensors have ceramic material
within them that can easily crack if
dropped or over-torqued. They must be
tightened to the specified torque figure with
a calibrated torque wrench. Care should be
taken not to contaminate the sensor tip
when the anti-seize compound is used on
the thread.
• To prevent damage to the sensors, a special tool (box spanner) should be used when
removing.
• If the sensor sticks in the exhaust, apply de- seize product and use a repeating tighten
and loosen strategy.
• Ensure that the sensor harness is robustly secured away from moving or hot parts. Failure Modes
• Mechanical fitting and integrity of the sensor (i.e.
cracked)
• Sensor open circuit/disconnected
• Short circuit to battery voltage or ground.
• Lambda ratio outside operating band
• Crossed sensors (RH bank fitted to LH bank and vice-versa)
• Contamination from leaded fuel or other sources
• Harness damage
• Air leak into exhaust system (cracked pipe/weld or loose fixings)
Failure Symptoms
• Default to open loop fuel metering
• High CO reading
• Strong smell of sulfur (rotten eggs) until default condition
• Excess emissions
• Unstable operation
• Reduced performance