2009 JAGUAR XF maf

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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)

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04/14/2009 NP10-V8JLR: AJ133 5.0-Liter DFI V8 Engine
Technical Training
Engine Coolant Temperature Sensor

Engine Management System

ENGINE COOLANT TEMPERATURE SENSOR
The engine coolant temperature (ECT) sensor is a nega-
tive temperature coefficient (NTC) thermistor, used to
monitor engine coolant temperature.
The ECT sensor is vital to the correct running of the
engine, as a richer mixture is required at lower block
temperatures for good quality starts and smooth running,
leaning off as the temperature rises to maintain emis-
sions and performance.
The sensor has a twist-lock design with a latch mecha-
nism, and is located at the rear of the engine in the water
crossover pipe, between the two heads.
Failure Modes
• Uses engine-off time and MAF for calculation
Failure Symptoms
• Poor cold and hot start
• Poor driveability
• Cooling fans on permanently
Sensor Resistance vs. Coolant Temperature
NOTE:
If the ECT sensor fails, the ECM uses a default
value. The electric fan control module is sent a default
coolant temperature value and switches the cooling
fan(s) on permanently.
The voltages shown represent the signal processed by
the ECM. When a defective coolant sensor is detected,
the coolant value defaults to 40°C (104°F) and remains
fixed until the ECM is powered down.
NP10V8099

Specification
Function
Supply voltage 5V ± 0.1V
Operating temperature range -30°C to 125°C
(-22°F – 257°F)
Pin 1 Sensor output signal
Pin 2 Sensor ground

Coolant Temperature
Approx. Resistance
-20°C (-4°F) 15.04 +0.90/-0.83 kOhms 20°C (68°F) 2.45 +0.10/-0.09 kOhms
80°C (176°F) 0.318 ±0.007 k Ohms
110°C (230°F) 0.1471 ±0.0018 k Ohms

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04/14/2009 NP10-V8JLR: AJ133 5.0-Liter DFI V8 Engine
Technical Training
Manifold Absolute Pressure Sensor

Engine Management System

MANIFOLD ABSOLUTE PRESSURE SENSOR
The manifold absolute pressure (MAP) sensor provides
a voltage proportional to the absolute pressure in the
intake manifold. This signal allows the load on the
engine to be calculated and used within the internal cal-
culations of the ECM.
The MAP sensor is mounted on the top of the engine, at
the front behind the throttle body. The purpose of the
sensor is to measure the absolute pressure in the intake
manifold and provide information to the ECM, which
will determine the injection time.
The sensor is a semi-conductor type, which responds to
pressure acting on a membrane within the sensor, alter-
ing the output voltage.
The sensor receives a 5V reference voltage and a ground
from the ECM and returns a signal of between 0.5 – 4.5V
to the ECM. A low pressure returns a low voltage signal to
the ECM and a high pressure returns a high voltage.
The MAP sensor detects quick pressure changes in the
intake manifold after the electronic throttle. The signal is
used in conjunction with the MAF sensor signal to calcu-
late the injection period. The ECM monitors the engine
MAP sensor for faults and can store fault related codes.
Failure Modes
• Sensor open circuit
• Short circuit to battery voltage or ground
• Intake air restricted
• Default value of 1 bar (14.5 psi)
Failure Symptoms
• Rough running
• Difficult starting
• Poor driveability
NP10V8101

Specification
Function
Power Source 5V ±0.25V
Pin 1 Power
Pin 2 Ground
Pin 3 Output Signal
Operating Range 13.3 kPa – 250 kPa

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