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

3-8
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)

3-3004/14/2009NP10-V8JLR: AJ133 5.0-Liter DFI V8 EngineTechnical Training
Controller Area Network Engine Management System
CONTROLLER AREA NETWORK
The Controller Area Network (CAN) is a high-speed
serial interface for sharing dynamic signals between elec-
tronic control modules. CAN communications are ‘self-
checked’ for errors, and if an error is detected the message
is ignored by the receiving electronic control module.
Due to the high rate of information exchange, the system
has a high degree of latency. This allows for a high num-
ber of errors to be present without reducing the data
transfer rate. In practice, this is a very reliable system.
Each CAN message is transmitted by one electronic con-
trol module and received by all other electronic control
modules on the CAN bus. Each message contains a fixed
structure of signals. The data exchanged is used so that
each electronic control module does not need to have a
hardwired sensor for each input. The CAN message iden-
tifiers are arranged by a network tool, which can guarantee
that all messages meet their specified timing needs.
Signal Overview
The CAN communication system is a differential bus
using a twisted pair that is normally very reliable. If either
or both of the wires of the twisted pair CAN bus is open-
or short-circuited, a CAN time-out fault will occur.
Below is a list of additional electronic control modules that
the ECM will communicate with on the CAN network:
• Instrument cluster
• Steering angle sensor
•TCM
• Active rear locking differential, if equipped
• Adaptive cruise control
• Electronic parking brake
Failure Modes
• CAN bus wiring short circuit or open circuit
• Incompatible software and message versions