Discovery 2. Manual - part 482

ENGINE MANAGEMENT SYSTEM - V8

DESCRIPTION AND OPERATION

18-2-7

The ECM controls the following outputs:

l

Fuel injectors (1 per cylinder).

l

Ignition coils/ high tension leads/ spark plugs. 

l

Fuel pump relay.

l

Idle air control valve.

l

Heated oxygen sensors.

l

EVAP canister purge valve.

l

EVAP canister vent solenoid (CVS) valve (where fitted).

l

Malfunction Indicator Lamp (MIL)/ service engine soon lamp (where fitted).

l

Hill descent control (via SLABS interface).

l

EVAP system fuel leak detection pump (where fitted)

l

Secondary air injection pump (where fitted)

The ECM also interfaces with the following:

l

Diagnostics via diagnostic connector with TestBook.

l

Controller Area Network (CAN) link to EAT ECU.

l

Air conditioning system.

l

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

l

Immobilisation system via the body control unit (BCU).

l

Instrument cluster.

l

Cruise control ECU

l

Active Cornering Enhancement (ACE) ECU

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:

l

NAS.

l

NAS low emission vehicles.

l

UK/ Europe/ Japan/ Australia.

l

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 reconfigured up to 16 times to meet changing specifications and legislation.

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.

ENGINE MANAGEMENT SYSTEM - V8

18-2-8

DESCRIPTION AND OPERATION

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.

Pin out details connector C0634

Connector 2 (C0635): This connector contains 24 pins and is primarily used for Heated Oxygen Sensors (HO

2

S) 

control and earth. The HO

2

S sensors require a heater circuit to assist in heating the tip of the sensors to enable closed 

loop fuelling to be implemented quickly after cold starting.

Pin out details connector C0635

Pin No.

Function

Signal type

Reading

1

Ignition position II

Input

12 V

2

Not used

-

-

3

Not used

-

-

4

Chassis earth

Earth

0V

5

Fuel injectors earth

Earth

0V

6

Power stage earth

Earth

0V

7

Permanent battery supply

Input battery supply

12V

8

Switched relay  positive

Input switched

0-12V

9

Not used

-

-

Pin No.

Function

Signal type

Reading

1

HO

2

S heater RH bank - downstream

Output

PWM 12-0V

2

Not used

-

-

3

Not used

-

-

4

Not used

-

-

5

Thermostat monitoring sensor

Earth

0V

6

Not used

-

-

7

HO

2

S heater LH bank - downstream

Output

PWM 12-0V

8

HO

2

S sensor RH bank - downstream

Earth/ Signal

0V

9

HO

2

S sensor LH bank - upstream

Earth/ Signal

0V

10

HO

2

S sensor RH bank - upstream

Earth/ Signal

0V

11

HO

2

S sensor LH bank - downstream

Earth/ Signal

0V

12

Not used

-

-

13

HO

2

S heater RH bank - upstream

Output

PWM 12-0V

14

HO

2

S sensor RH bank - downstream

Input/ Signal

Analogue 0-5V

15

HO

2

S sensor LH bank - upstream

Input/ Signal

Analogue 0-5V

16

HO

2

S sensor RH bank - upstream

Input/ Signal

Analogue 0-5V

17

HO

2

S sensor LH bank - downstream

Input/ Signal

Analogue 0-5V

18

Fuel pump relay

Output

Switch to earth

19

HO

2

S heater LH bank - upstream

Output

PWM 12-0V

20

Not used

-

-

21

Thermostat monitoring sensor

Signal

Analogue 0-5V

22

Not used

-

-

23

Main relay

Output

Switch to earth

24

EVAP system leak detection pump motor (NAS 
vehicles with positive pressure type, EVAP system 
leak detection capability only)

Output

Switch to earth

ENGINE MANAGEMENT SYSTEM - V8

DESCRIPTION AND OPERATION

18-2-9

Connector 3 (C0636): This connector contains 52 pins and is used for most sensor and actuator inputs and outputs. 
Sensor and actuator control is vital to ensure that the ECM maintains adaptive strategy

Pin out details connector C0636

Pin No.

Function

Signal type

Reading

1

Injector cylinder number 2

Output

Switch to earth

2

Injector cylinder number 5

Output

Switch to earth

3

Purge valve

Output, signal

PWM 12-0V

4

SAI vacuum solenoid valve (NAS vehicles from 
2000MY only)

Output

Switch to earth

5

Not used

-

-

6

Fuel tank pressure sensor (NAS vehicles with 
vacuum type, EVAP system leak detection 
only)

Earth

0V

7

MAF sensor 5V supply

Output, reference

5V

8

Not used

-

-

9

MAF sensor earth

Earth

0V

10

TP sensor 5V supply

Output, reference

5V

11

Not used

-

-

12

Not used

-

-

13

Not used

-

-

14

Injector cylinder number 7

Output

Switch to earth

15

Injector cylinder number 6

Output

Switch to earth

16

SAI pump relay (NAS vehicles from 2000MY 
only)

Output

Switch to earth

17

CMP sensor

Earth

0V

18

Low range switch (manual transmission only)

Input, signal

Active low

19

Not used

-

-

20

CMP signal

Input, signal

Digital switch 0-12V

21

ECT sensor

Earth

0V

22

Coolant temperature signal

Input, signal

Analogue 0-5V

23

MAF sensor signal

Input, signal

Analogue 0-5V

24

TP sensor signal

Input, signal

Analogue 0-5V

25

TP sensor earth

Earth

0V

26

Not used

-

-

27

Injector cylinder number 3

Output

Switch to earth

28

Injector cylinder number 8

Output

Switch to earth

29

Hill decent control output

Output, signal

PWM 0-12V

30

EVAP canister vent solenoid (CVS) valve (NAS 
vehicles with vacuum type, EVAP system leak 
detection only)

Output

Switch to earth

30

Leak detection pump solenoid (NAS vehicles 

with positive pressure type, EVAP system leak 

detection only)

Output

Switch to earth

31

A/C condenser fan

Output

Switch to earth

32

CKP sensor signal

Input, signal

Analogue, 0-300V peak

33

Not used

-

-

34

IAT sensor signal

Input, signal

Analogue 0-5V

35

KS, RH bank earth

Earth

0V

36

KS, RH bank signal

Input, signal

Analogue

37

Not used

-

-

38

Not used

-

-

39

Not used

-

-

40

Injector cylinder number 4

Output

Switch to earth

41

Injector cylinder number 1

Output

Switch to earth

ENGINE MANAGEMENT SYSTEM - V8

18-2-10 DESCRIPTION AND OPERATION

Connector 4 (C0637): This connector contains 40 pins and facilitates use of TestBook via the Diagnostic connector. 
Also contained in this connector is the Malfunction Indicator Lamp (MIL), this instrument panel lamp informs the driver 
of concerns within the engine management system.

Pin out details connector C0637

42

Idle air control valve open

Output, signal

PWM 12-0V

43

Idle air control valve close

Output, signal

PWM 12-0V

44

ECT sensor signal

Output, signal

PWM 0-12V

45

CKP sensor earth screen

Earth

0V

46

CKP sensor signal

Earth reference

0V

47

Not used

-

-

48

KS, LH bank earth

Earth

0V

49

KS, LH bank signal

Input, signal

Analogue

50

Not used

-

-

51

Not used

-

-

52

Not used

-

-

Pin No.

Function

Signal type

Reading

1

Not used

-

-

2

Not used

-

-

3

Not used

-

-

4

Not used

-

-

5

Not used

-

-

6

Not used

-

-

7

Not used

-

-

8

Low fuel level

Input, signal

Active high

9

Fuel tank pressure sensor (NAS vehicles with 
vacuum type, EVAP system leak detection 
capability only)

Output, reference

5V

10

Not used

-

-

11

Not used

-

-

12

Analogue fuel level (NAS vehicles with positive 
pressure type, EVAP system leak detection only)

Input, signal

0-5V

13

Not used

-

-

14

Fuel tank pressure sensor (NAS vehicles with 
vacuum type, EVAP system leak detection 
capability only)

Input, signal

Analogue 0-5V

15

Not used

-

-

16

ATC compressor request

Input, signal

Active low

17

Engine speed output

Output, signal

PWM 0-5V

18

Not used

-

-

19

Not used

-

-

20

Malfunction indicator lamp 'ON'

Output

Switched earth

21

Not used

-

-

22

Vehicle speed signal (VSS)

Input, signal

PWM 0-12V

23

Not used

-

-

24

Not used

-

-

25

Not used

-

-

26

Not used

-

-

27

Not used

-

-

28

Not used

-

-

29

ATC compressor relay

Output

Switched earth

30

Not used

-

-

Pin No.

Function

Signal type

Reading