2010 JAGUAR XFR ignition

Published: 11-May-2011
Evaporative Emissions - V8 5.0L Petrol/V8 S/C 5.0L Petrol - Evaporative Emissions - System Operation and Component Description
Description and Operation

System Operation DIAGNOSTIC MODULE - TANK LEAKAGE PUMP (NAS ONLY)
To check the fuel tank and the EVAP (evaporative emission) system for leaks, the ECM (engine control module) operates the
DMTL pump and monitors the current draw. Initially, the ECM establishes a reference current by pumping air through the reference orifice and back to atmosphere. Once the reference current is determined, the ECM closes the change-over valve, which seals the EVAP system. The EVAP canister purge valve remains de-energized and is therefore closed. The output from the air pump is diverted from the reference orifice and into the EVAP system.
When the change-over valve is closed, the load on the air pump falls to zero. Providing there are no leaks, the air pump will
begin to pressurize the EVAP system and the load and current draw in the pump increases. By monitoring the rate and level of the current increase, the ECM can determine if there is a leak in the EVAP system.
During normal vehicle operation, 15 seconds after the engine has started, the ECM energizes the heating element in the pump to prevent condensation formation and possible incorrect readings. The heater remains energized until either the engine and
ignition are off (if no DMTL test is running) or until after the DMTL test is completed.
Leaks are classified as:

Minor - equivalent to a hole diameter of 0.5 to 1.0 mm (0.02 to 0.04 in.).
Major - equivalent to a hole diameter of 1.0 mm (0.04 in.) or greater.
The ECM performs a check for major leaks each time the ignition is switched off, providing the following conditions are met: The vehicle speed is zero.
The engine speed is zero.
The atmospheric pressure is above 70 kPa (10.15 lbf/in2
), i.e. the altitude is less than approximately 3047 m (10000
feet).
The ambient temperature is between 0 and 40 °C (32 and 104 °F).
The EVAP canister vapor concentration factor is 5 or less (where 0 is no fuel vapor, 1 is stoichiometric fuel vapor and greater than 1 is rich fuel vapor).
The fuel tank level is valid and between 15 and 85% of nominal capacity.
The engine running time during the previous cycle was more than 10 minutes.
The battery voltage is between 10 and 15 volts.
The last engine off time was more than 180 minutes.
No errors are detected with the EVAP components, the ambient air temperature and the fuel level.

NOTE: A leak test can be performed using a Jaguar recognized diagnostic tool. This overrides the above conditions and is
useful for checking correct system and component operation.
The ECM performs a check for minor leaks after every 2nd major leak check.
When the leak check is complete, the ECM stops the DMTL pump and opens (de-energizes) the change-over valve.
If the fuel filler cap is opened or refueling is detected during the leak check, by a sudden drop in the current draw or a rise in
the fuel level, the ECM aborts the leak check.
If a leak is detected during the check, the ECM stores an appropriate fault code in its memory. If a leak is detected on two consecutive checks, the ECM illuminates the MIL (malfunction indicator lamp) in the instrument cluster on the next drive cycle. The duration of a leak check can be between 60 and 900 seconds depending on the results and fuel tank level.

EVAP CANISTER PURGE VALVE

The ECM waits until the engine is running above 55 °C (131 °F) coolant temperature with closed loop fuel operational before the purging process is activated. Under these conditions the engine should be running smoothly with no warm up enrichment.
The EVAP canister purge valve duty (and flow) is initially ramped slowly because the vapor concentration is unknown (a sudden increase in purge could cause unstable engine running or cause it to stall due to an extremely "rich" air/fuel mixture). The
concentration is then determined from the amount of adjustment that the closed loop fueling is required to make to achieve
the target AFR (air fuel ratio). Once the concentration has been determined, the purge flow can be increased rapidly and the
injected fuel can be pro-actively adjusted to compensate for the known purge vapor and the target AIR control is maintained.

When the purging process is active, fresh air is drawn into the EVAP canister via the DMTL filter and pump on NAS vehicles, or via the vent port on the EVAP canister of non NAS vehicles.

Component Description DIAGNOSTIC MODULE - TANK LEAKAGE PUMP (NAS ONLY)













The DMTL (diagnostic module - tank leakage) pump periodically checks the EVAP system and the fuel tank for leaks when the ignition is switched off. The DMTL system comprises the previously described components of the EVAP system with the following additional components; a DMTL pump and a DMTL filter.

The DMTL pump is connected to the atmospheric vent of the EVAP canister and incorporates an electric air pump, a PTC (positive temperature coefficient) heating element, a normally open change-over valve and a reference orifice. The DMTL pump
is only operated when the ignition is switched off and is controlled by the ECM. The ECM also monitors the electric air pump operation and the change-over valve for faults.

The DMTL filter protects the pump from dust being drawn into the system when the pump is being operated. The filter is
located on the fuel filler head and is connected to the DMTL pump by a vapor pipe.

The DMTL test is performed after the engine has stopped following a run of 10 minutes or more, providing that the vehicle fuel
tank is between 15 and 85% full, the ambient temperature is above 0 °C (32 °F) and less than 40 °C (104 °F) and the vehicle
was not started for at least 180 minutes prior to this run.

The DMTL pump is driven to pressurize the fuel tank and the current is measured with the change-over valve in different
states.

A comparison of the current draw in each state indicates the degree of any leak, and the ECM then sets the appropriate DTC (diagnostic trouble code).
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Published: 11-May-2011
Electronic Engine Controls - V8 S/C 5.0L Petrol - Electronic Engine Controls - Overview
Description and Operation

OVERVIEW

The EEC (electronic engine control) system operates the engine to generate the output demanded by the accelerator pedal and
loads imposed by other systems. The EEC system has an ECM (engine control module) that uses a torque-based strategy to evaluate inputs from sensors and other systems, then produces outputs to engine actuators to produce the required torque.
The EEC system controls the following: Charge air
Fueling
Ignition timing
Valve timing
Cylinder knock
Noise feedback system
Idle speed
Engine cooling fan
Evaporative emissions
On-board diagnostics
Immobilization system interface
Speed control.

DIAGNOSTICS

The ECM stores each fault as a DTC (diagnostic trouble code). The DTC and associated environmental and freeze frame data can be read using Jaguar approved diagnostic equipment, which can also read real time data from each sensor, the adaption
values currently being employed and the current fueling, ignition and idle speed settings.



ENGINE CONTROL MODULE Component Description



The ECM is installed in the front passenger side of the engine compartment, on a bracket attached to the engine bulkhead. The ECM has the capability of adapting its fuel and ignition control outputs in response to several sensor inputs. The ECM receives inputs from the following:
CKP sensor. CMP (camshaft position) sensors (4 off).
ECT (engine coolant temperature) sensor.
Knock sensors (4 off).
MAP (manifold absolute pressure) sensor.
MAFT sensors (2 off). MAPT (manifold absolute pressure and temperature) sensor.
Throttle position sensor.
Heated oxygen sensors (4 off).
APP sensor. Ambient air temperature sensor.
FRP (fuel rail pressure) sensor. For additional information, refer to 303-04G Fuel Charging and Controls.
Engine cooling fan. For additional information, refer to 303-03D Engine Cooling.
Stoplamp switch. For additional information, refer to 206-09 Anti-Lock Control - Stability Assist.
Speed control cancel/suspend switch. For additional information, refer to 310-03D Speed Control.
Oil level and temperature sensor. For additional information, refer to 303-01F Engine.
Fuel LP (low pressure) sensor. For additional information, refer to 310-01D Fuel Tank and Lines.
Fuel pump driver module. For additional information, refer to 310-01D Fuel Tank and Lines.
The ECM provides outputs to the following: Electronic throttle.
Main relay.
Heater elements of the heated oxygen sensors (4 off).
Fuel injectors (8 off). For additional information, refer to 303-04G Fuel Charging and Controls. www.JagDocs.com

Defaults to base mapping for the ignition timing, with no cylinder correction
Disables the VCT system.
ENGINE COOLANT TEMPERATURE SENSORS



The ECT sensors are NTC (negative temperature coefficient) thermistors that allow the ECM to monitor the engine coolant temperature.

There are two identical ECT sensors installed, which are identified as ECT 1 and ECT 2. Each sensor is secured with a twist-lock and latch mechanism, and is sealed with an O-ring. A two pin electrical connector provides the interface between the sensor
and the engine harness.

ECT 1

ECT 1 is installed in the heater manifold, at the rear of the RH (right-hand) cylinder head. The input from this sensor is used in
calibration tables and by other systems.

ECT 2

ECT 2 is installed in the lower hose connector which attaches to the bottom of the thermostat. The input from this sensor is
used for OBD (on-board diagnostic) 2 diagnostics and, in conjunction with the input from ECT 1, to confirm that the thermostat
is functional.

KNOCK SENSORS



The knock sensors are piezo-ceramic sensors that allow the ECM to employ active knock control and prevent engine damage from pre-ignition or detonation.

Two knock sensors are installed on the inboard side of each cylinder head, one mid-way between cylinders 1 and 2, and one
mid-way between cylinders 3 and 4. Each knock sensor is secured with a single screw. On each knock sensor, a two pin
electrical connector provides the interface with the engine harness.

The ECM compares the signals from the knock sensors with mapped values stored in memory to determine when detonation occurs on individual cylinders. When detonation is detected, the ECM retards the ignition timing on that cylinder for a number of engine cycles, then gradually returns it to the original setting.

The ECM cancels closed loop control of the ignition system if the signal received from a knock sensor becomes implausible. In these circumstances the ECM defaults to base mapping for the ignition timing. This ensures the engine will not become damaged if low quality fuel is used. The MIL (malfunction indicator lamp) will not illuminate, although the driver may notice
that the engine 'pinks' in some driving conditions and displays a drop in performance and smoothness.

MANIFOLD ABSOLUTE PRESSURE AND TEMPERATURE SENSOR













The MAPT sensor allows the ECM to calculate the air charge density immediately before it enters the cylinders. This is used to adjust the ignition timing relative to the boost pressure, and to monitor the performance of the charge air coolers.

The MAPT sensor is installed in the rear of the LH intake manifold. The sensor is secured with a single screw and sealed with an O-ring. A four pin electrical connector provides the interface with the engine harness.

THROTTLE POSITION SENSORS

The TP (throttle position) sensors allow the ECM to determine the position and angular rate of change of the throttle blade. There are two TP sensors located in the electronic throttle. See below for details of the electronic throttle. If aTP sensor fails, the ECM:
Adopts a limp home mode where engine speed is limited to a maximum of approximately 2000 rev/min
Discontinues evaporative emissions control
Discontinues closed loop control of engine idle speed.

With a failed TP sensor, the engine will suffer from poor running and throttle response.
HEATED OXYGEN SENSORS



Item Description A Upstream heated oxygen sensor B Downstream heated oxygen sensor The heated oxygen sensors allow the ECM to measure the oxygen content of the exhaust gases, for closed loop control of the fuel:air mixture and for catalytic converter monitoring.

An upstream heated oxygen sensor is installed in the outlet of each exhaust manifold, which enables independent control of
the fuel:air mixture for each cylinder bank. A downstream heated oxygen sensor is installed in each catalytic converter, which
enables the performance of the catalytic converters to be monitored.

Oxygen sensors need to operate at high temperatures in order to function correctly. To achieve the high temperatures required,
the sensors are fitted with heater elements that are controlled by a PWM (pulse width modulation) signal from the ECM. The heater elements are operated immediately after each engine start and during low load conditions when the temperature of the
exhaust gases is insufficient to maintain the required sensor temperature. The PWM duty cycle is carefully controlled to prevent thermal shock to cold sensors. A non-functioning heater delays the sensor’s readiness for closed loop control and
increases emissions.

The upstream heated oxygen sensors produce a constant voltage, with a variable current that is proportional to the lambda
ratio. The downstream heated oxygen sensors produce an output voltage dependant on the ratio of the exhaust gas oxygen to

around the vehicle. The ECM uses the AAT input for a number of functions, including engine cooling fan control. The ECM also transmits the ambient temperature on the high speed CAN bus for use by other control modules.
The AAT sensor is installed in the LH (left-hand) exterior mirror, with the bulb of the sensor positioned over a hole in the
bottom of the mirror casing.

The ECM supplies the sensor with a 5 V reference voltage and a ground, and translates the return signal voltage into a temperature.

If there is a fault with the AAT sensor, the ECM calculates the AAT from the temperature inputs of the MAFT sensors. If the AAT sensor and the temperature inputs of the MAFT sensors are all faulty, the ECM adopts a default ambient temperature of 20 °C (68 °F).

ELECTRONIC THROTTLE


The ECM uses the electronic throttle to regulate engine torque.
The electronic throttle is installed between the T piece duct, of the intake air distribution and filtering system, and the inlet of
the SC. For additional information, refer to 303-12F Intake Air Distribution and Filtering.
The throttle plate is operated by an electric DC (direct current) motor integrated into the throttle body. The ECM uses a PWM signal to control the DC motor. The ECM compares the APP sensor inputs against an electronic map to determine the required position of the throttle plate. The ECM and electronic throttle are also required to: Monitor requests for cruise control operation
Automatically operate the electronic throttle for accurate cruise control
Perform all dynamic stability control engine interventions
Monitor and carry out maximum engine speed and road speed cut outs
Provide different engine maps for the ride and handling optimization system.

A software strategy within the ECM calibrates the position of the throttle plate at the beginning of each ignition cycle. When the ignition is turned on, the ECM performs a self test and calibration routine by fully closing the throttle plate and then opening it again. This tests the default position springs and allows the ECM to learn the position of the closed hard stop. Subsequently the ECM keeps the throttle plate a minimum of 0.5 degree from the closed hard stop. AMBIENT AIR TEMPERATURE SENSOR

(engine junction box).

When the ignition is turned on, battery voltage is applied to the ignition sense input. The ECM then starts its power up routines and energizes the main relay.

When the ignition is turned off, the ECM maintains its powered up state while it conducts the power down routines (up to 20 minutes in extreme cases, when cooling fans are required) and on completion will turn off the main relay.