Discovery 2. Manual — part 69

ENGINE MANAGEMENT SYSTEM - V8

DESCRIPTION AND OPERATION

18-2-5

1 Engine control module
2 Crankshaft speed and position sensor
3 Camshaft position sensor
4 Engine coolant temperature sensor
5 Mass air flow/ inlet air temperature sensor
6 Throttle position sensor
7 Heated oxygen sensors
8 Fuel injectors
9 Idle air control valve

10 Fuel pump relay
11 EVAP canister
12 EVAP canister vent valve
13 EVAP canister purge valve
14 Fuel tank pressure sensor

15 Ignition coils
16 Knock sensor
17 Spark plugs
18 High/ Low ratio switch
19 Malfunction indication lamp
20 Diagnostic connector
21 Air temperature control clutch relay
22 Air temperature control cooling fan relay
23 ATC ECU
24 CAN link to EAT
25 SLABS ECU
26 BCU
27 Instrument cluster
28 Thermostat monitoring sensor (where fitted)

ENGINE MANAGEMENT SYSTEM - V8

18-2-6

DESCRIPTION AND OPERATION

Description - engine management

General
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)

ENGINE MANAGEMENT SYSTEM - V8

DESCRIPTION AND OPERATION

18-2-7

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).

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EVAP system fuel leak detection pump (where fitted)

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Secondary air injection pump (where fitted)

The ECM also interfaces with the following:

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Diagnostics via diagnostic connector with TestBook.

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Controller Area Network (CAN) link to EAT ECU.

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Air conditioning system.

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Self Levelling & Anti-lock Braking System (SLABS) ECU.

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Immobilisation system via the body control unit (BCU).

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Instrument cluster.

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Cruise control ECU

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Active Cornering Enhancement (ACE) ECU

ENGINE MANAGEMENT SYSTEM - V8

18-2-8

DESCRIPTION AND OPERATION

Engine Control Module (ECM)

The engine control module (ECM) is located on the RH side A post below the face panel inside the vehicle. It has a
cast aluminium case and is mounted on a bracket. The ECM has 5 independent connectors totalling 134 pins.

The ECM is available in 4 variants:

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NAS.

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NAS low emission vehicles.

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UK/ Europe/ Japan/ Australia.

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ROW/ Gulf.

The ECM uses a 'flash' electronic erasable programmable read only memory (EEPROM). This enables the ECM to
be externally configured, to ensure that the ECM can be updated with any new information, this also allows the ECM
to be configured with market specific data. TestBook must be used to configure replacement ECM's. The ECM can
be reprogrammed, using TestBook/T4, with new engine tunes up to 16 times to meet changing specifications and
legislation. The current engine tune data can be accessed and read using TestBook/T4.

The ECM memorises the positions of the crankshaft and the camshaft when the engine has stopped via the CKP and
CMP sensors. This allows immediate sequential fuel injection and ignition timing during cranking. This information is
lost if battery voltage is too low (i.e. flat battery). So the facility will be disabled for the first engine start.

Input/Output
The ECM has various sensors fitted to the engine to allow it to monitor engine condition. The ECM processes these
signals and decides what actions to carry out to maintain optimum engine operation by comparing the information
from these signals to mapped data within its memory.

Connector 1 (C0634): This connector contains 9 pins and is used primarily for ECM power input and earth. The ECM
requires a permanent battery supply, if this permanent feed is lost i.e. the battery discharges or is disconnected the
ECM will lose its adapted values and its Diagnostic Trouble Codes (DTC). These adapted values are a vital part of
the engine management's rolling adaptive strategy. Without an adaptive strategy, driveability, performance, emission
control, and fuel consumption are adversely affected. The ECM can be damaged by high voltage inputs, so care must
be taken when removing and replacing the ECM.