Discovery II (LT) V8-4.0L (2002)
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Engine Control Module: Description and Operation
General Description
The V8 engine is equipped with the Bosch Motronic M5.2.1 engine management system. This system is a sequential multiport fuel injection system
controlled by an Engine Control Module (ECM).
A single ECM is used for the control of the existing 4.0 litre engine and the new 4.6 litre engine introduced with 03 model year vehicles for the NAS
market only. The ECM contains the tunes for both engines variants. When the ECM is replaced, TestBook/T4 must be used to select the correct tune to
match the engine fitment.
The ECM has On Board Diagnostic (OBD) strategies as required by various market legislative bodies. To meet these requirements the system monitors
and reports on any faults that cause excessive exhaust emissions.
In markets that mandate OBD, the ECM monitors performance of the engine for misfires, catalyst efficiency, exhaust leaks and evaporative control loss.
If a fault occurs, the ECM stores the relevant fault code and warns the driver of component failure by illuminating the Malfunction Indicator Light in the
instrument pack.
In markets where OBD is not mandatory, the ECM will still monitor performance of the engine and store the fault code, but will not illuminate the
Malfunction Indicator Light.
The ECM uses input and output information from its sensors and actuators to control the following engine conditions:
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Fuel quantity.
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Closed loop fuelling.
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Open loop fuelling.
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Ignition timing.
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Knock control.
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Idle speed control.
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Emission control.
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On-Board Diagnostic (OBD) where applicable.
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Vehicle immobilisation.
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Misfire detection (where applicable).
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Vehicle speed signal.
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Rough road signal (where applicable).
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Low fuel level signal (where applicable).
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Coolant temperature gauge signal.
The ECM processes sensor information from the following input sources:
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Ignition switch (position II).
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Crankshaft speed and position sensor.
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Camshaft position sensor.
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Engine coolant temperature sensor.
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Mass air flow sensor.
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Intake air temperature sensor.
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Knock sensor.
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Throttle position sensor.
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Heated oxygen sensors.
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High/ Low ratio switch.
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Fuel tank pressure sensor (where fitted)
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Thermostat monitoring sensor (where fitted)
The ECM controls the following outputs:
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Fuel injectors (1 per cylinder).
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Ignition coils/ high tension leads/ spark plugs.
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Fuel pump relay.
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Idle air control valve.
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Heated oxygen sensors.
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EVAP canister purge valve.
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EVAP canister vent solenoid (CVS) valve (where fitted).
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Malfunction Indicator Lamp (MIL)/ service engine soon lamp (where fitted).
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Hill descent control (via SLABS interface).
