2009 JAGUAR XF ignition

Technical TrainingNP10-V8JLR: AJ133 5.0-Liter DFI V8 Engine04/14/20093-19
Engine Management SystemThrottle Position Sensor
THROTTLE POSITION SENSOR
The engine torque is regulated via an electronic throttle
body (‘drive-by-wire’ system), where an electronic pedal
assembly determines throttle opening.
The throttle position (TP) sensor is mounted in the inte-
grated cover plate on the throttle body assembly. The
throttle body assembly is mounted at the top front of the
engine, in a similar position for both NA and SC variants.
This value is input into the ECM and the throttle is
opened to the correct angle by means of an electric direct
current (DC) motor integrated into the throttle body.
Movement of the motor is achieved by changing the
PWM signal to the DC motor, allowing it to be operated
in both directions.
The dual-output TP sensor in the throttle body is used to
determine the position of the throttle blade and the rate
of change in its angle.
A software strategy within the ECM enables the throttle
position to be calibrated each ignition cycle. When the
ignition is turned ON, the ECM commands the throttle
to open and close fully, thus performing a self-test and
calibration, learning the position of the full closed hard
stop position.Safety Precautions
CAUTION: Terminals in sensor and connec-
tor are gold-plated for corrosion/temperature
resistance – DO NOT probe.
Failure Modes
• Sensor open circuit
• Short circuit to battery voltage or ground
• If signal failure occurs the ECM will enter a limp home mode where the maximum engine speed is
2000 rpm
• Signal offset
• Vacuum leak
Failure Symptoms
• Poor engine running and throttle response
• Limp home mode – maximum 2000 rpm
• Emission control failure
• No closed loop idle speed control
NP10V8105
SpecificationFunction
Supply voltage 5V ± 0.2 V
Supply current Max. 10 mA/1 output
Tolerance – closed position ±150 mV Tolerance – WOT position ±150 mV
Operating temperature range -40°C – 160°C
(-40°F – 320°F)
Pin 1 Throttle motor valve open:
direction +
Pin 2 Throttle motor valve open:
direction –
Pin 3 Position sensor output 2
(Gold)
Pin 4 Ground (Gold)
Pin 5 Position sensor output 1
(Gold)
Pin 6 Position sensor 5V supply
(Gold)

Technical TrainingNP10-V8JLR: AJ133 5.0-Liter DFI V8 Engine04/14/20093-27
Engine Management SystemIgnition Coils
IGNITION COILS
The ignition coil operates according to the laws of induc-
tion. The unit consists of two magnetically-coupled cop-
per coils (primary and secondary windings).The coil has
a 3-pin connector and incorporates an internal switching
module.
Energy is stored in the primary winding’s magnetic field
by allowing a current to flow through the primary circuit
switched by the switching module.
At the firing point the current flow is interrupted by the
ECM, which induces secondary voltage in the coil’s sec-
ondary winding.
The secondary circuit has a diode on the ground side in
order to reduce any undesired switch-on voltage, which
could lead to misfiring into the intake manifold to an
uncritical value.
The switching module will limit the primary current to a
maximum value. It also limits the maximum primary
voltage by voltage clamping. This protects the switching
module and (along with other parameters) determines
the maximum possible secondary voltage. Safety Precautions
WARNING:
• Ignition coils generate high voltages that can cause personal injury. Appropriate
safety instructions on handling high volt-
ages must be observed.
CAUTIONS:
• The spark plugs fitted are critical to the performance of the ignition and misfire
detection systems. No attempt should be
made to ‘clean’ or ‘gap’ these spark plugs.
They are very reliable and unlikely to cause
problems. If a faulty spark plug is sus-
pected, try substituting it before condemn-
ing it. It is essential that only factory-
approved spark plugs be used in service.
DO NOT attempt to use ‘equivalent’ spark
plugs, even if they are of a similar design.
Use of unapproved spark plugs will cause
the misfire detection system to malfunction
and erroneously store misfire faults.
• To avoid damage to the insulator, always use the correct specified spark plugs and correct
plug removal/refit plug socket.
NOTE: A single capacitor is used in the engine harness to
suppress interference from the ignition coil power supply.
Radio Frequency Interference Suppressor
The radio frequency interference (RFI) suppressor is
mounted on the harness carrier bracket on at the upper
rear of the engine.
NP10V8109
NP10V8110

Technical TrainingNP10-V8JLR: AJ133 5.0-Liter DFI V8 Engine04/14/20093-31
Engine Management SystemOn-Board Diagnostic Monitoring
ON-BOARD DIAGNOSTIC MONITORING
Some OBD monitors are continuous, that is they operate
all the time the ignition is on.
Some OBD monitors have conditions that must be met
before the monitor is allowed to operate, such as engine
speed 1000 – 4000 rpm and engine airflow 10 – 100 g/
sec and intake air temperature -10 – +50°C, in order to
ensure the vehicle is operating in such a manner that the
failure may be correctly diagnosed. For this reason it
may be possible for a failure to be present on the vehicle
but remain undetected by the module.
Most OBD monitors use 2-trip detection: if on the first
occasion the failure is detected, a pending DTC is
recorded. If the failure is again detected on the next drive
cycle, then a confirmed DTC is logged and the MIL may
be illuminated.
A few OBD monitors operate on a single-trip basis
where the MIL is illuminated as soon as the failure is
diagnosed.
Detection of a failure may prevent the operation of other
OBD monitors. This is to prevent the logging of multiple
DTCs for a single. However, the system is not infallible,
and a single fault may result in two or more failures
being detected, with two or more DTCs being recorded.